Review Sheet – Biology EOC

1. Biomolecules and Enzymes

a. Biomolecules - Large complex molecules (polymer) made up of repeating subunits (monomers)

i. Carbohydrates

1. Elements: carbon, hydrogen, and oxygen (1:2:1 ratio)

2. Subunit: monosaccharide (sugar)

3. Examples: fruits, veggies, bread, pasta, potatoes, and rice

4. Uses

a. Immediate energy

b. Cellulose (cell walls)

c. Cell membrane signaling and storage

ii. Lipids

1. Elements: carbon, hydrogen, and oxygen

2. Subunits: fatty acid chains and glycerol

3. Examples: fats (butter), oils, and waxes

4. Uses

a. Long-term energy (keeps you warm)

b. Phospholipids (cell membrane)

c. Steroids – cholesterol and hormones

iii. Proteins

1. Elements: carbon, hydrogen, oxygen, nitrogen (and sometimes sulfur)

2. Subunit: amino acids connect with peptide bonds

3. Examples: meat, eggs, fish, nuts, and beans

4. Uses

a. Enzymes – speed up chemical reactions

b. Component of most organelles (including cell membrane)

c. Regulates hormones, repairs injuries, controls muscle movement, storage

d. Transport of molecules across the cell membrane

5. Levels of structure

a. Primary – amino acid chain

b. Secondary – alpha helix and beta pleated sheet

c. Tertiary – globular

iv. Nucleic Acids

1. Elements: carbon, hydrogen, oxygen, nitrogen, and phosphorous

2. Subunit: nucleotides

3. Examples: DNA and RNA

4. Uses – store and transmit genetic information

b. Formation of polymers – Dehydration Synthesis: water removed to bind 2 monomers together

c. Breakdown of polymers – hydrolysis: water added to break the bonds of a polymer to divide into its

constituent monomers

d. Enzymes

i. Proteins that speed up chemical reactions, also called catalysts

ii. Remain unchanged by the reaction, do not get used up. They cannot increase how much of the

product gets made

iii. Lower activation energy (minimum energy needed for a chemical reaction to occur)

iv. If there were no enzymes, you would need higher temperatures for reactions to occur

v. They have a specific shape, which determines which substrate they work with (lock-and-key)

vi. Substrates bind to the enzymes active site; the enzyme “hugs” the substrate – induced fit

vii. Specificity = only one substrate can bind with one enzymes

viii. Co-enzymes – a non-protein component of some enzymes

ix. Rate of enzyme activity depends on

1. Its shape

2. Temperature – temp too low/high, enzyme activity slow down. Temp WAY too high,

enzyme denatures (comes apart)

3. pH – number of hydrogen ion in solution

4. Concentration – the larger the concentration of the enzymes, the faster the reaction (to

a point)

2. Cell Structure and Transport

a. History

i. Robert Hooke – looked at cork; named cells (“little rooms”)

ii. Matthias Schleidan – all plants are made of cells

iii. Theodore Schwann – all animals are made of cells; all living things are made of cells

iv. Rudolf Virchow – all cells come from other living cells

b. Cell Theory

i. All living things are composed of cells

ii. Cells are the basic unit of structure and function in living things (cell = smallest unit capable of

performing life functions)

iii. All cells come from preexisting cells through cell division/mitosis

c. Levels of Organization (small to large): atom molecule/compound organelle cell tissue

organ organ system organism population community ecosystem biosphere

d. Prokaryote vs. Eukaryote

i. ALL cells have DNA, ribosomes, cytoplasm, and a cell membrane (DR.CC)

1. Only animals and animal-like protists lack a cell wall

ii. Prokaryote

1. Simplest type – NO membrane bound organelles

2. Unicellular

3. Eubacteria and archaea are the only organisms in this group

4. Reproduce via binary fission (asexual) or conjugation (sexual)

iii. Eukaryote

1. Complex – DO have membrane bound organelles (including a nucleus)

2. Most are multicellular (some are unicellular)

3. Most living organisms – protists, fungi, plants, and animals

4. Reproduce via mitosis (somatic cells) or meiosis (gametes)

e. Organelle Structure and Function (organelles are small structures that perform various functions for the

cell)

i. Cell Wall

1. Found in bacteria, fungi, and plants (outside the cell membrane)

2. Supports and protects

ii. Cell Membrane

1. Phospholipid bilayer that surrounds ALL cells

2. Controls movement into and out of the cell (semi-permeable) to maintain homeostasis

iii. Cytoplasm : Gel-like mix (80% water) that protects the organelles

iv. Nuclear Membrane – phospholipid bilayer that surrounds the nucleus

v. Nucleus – contains genetic material (DNA) and controls all cell activities

vi. Nucleolous – inside the nucleus; makes ribosomes

vii. Chromosomes – made of DNA and contain the instructions for traits and characteristics

viii. Mitochondria – Produces ATP (energy); has its own DNA and its own ribosomes

ix. Rough ER – hollow tubes that is studded with ribosomes and transports proteins to the Golgi

x. Smooth ER – Makes steroids, ions, and other lipids and transports the to the Golgi; detoxifies

poisons and drugs

xi. Ribosomes – make protein

xii. Golgi – modifies, sorts, and packages molecules from the ER and distributes them with vesicles

xiii. Lysosome – has digestive enzymes that break down wastes and old cell parts

xiv. Vacuole – stores water, food, and wastes; maintains the shape of plant cells (turgor pressure)

xv. Chloroplast – site of photosynthesis, contains chlorophyll which makes plants green

xvi. Cilia/flagella – traps particles/provide movement for a cell

f. Cell Transport

i. Homeostasis: maintaining a stable body system. Maintained in our cells by the cell membrane

ii. Cell membrane

1. Selectively permeable – lets some things in/out but not others

2. Phospholipids – hydrophilic (water loving) heads and hydrophobic (water fearing) tails

iii. Concentration gradient

1. A high concentration of molecules in one area, spreading out to a low concentration of

molecules in another area

2. The molecules NATURALLY want to spread out into the area of low concentration until

they are evenly spread out

iv. Passive Transport – the movement of molecules DOWN/WITH their concentration gradient

without using energy (from high to low concentration)

1. Diffusion: movement of small molecules from high to low concentration

2. Facilitated diffusion – movement of small molecules with the help of proteins

3. Osmosis: movement of water molecules from high to low concentration

4. Factors that affect diffusion

a. Temperature – as the temp increases, so does the rate of diffusion

b. Size of the molecule – smaller molecules diffuse faster than larger ones

c. Concentration – the greater the difference in concentration between two areas,

the faster the rate of diffusion will be

v. Active transport – movement of molecules UP/AGAINST their concentration gradient, which

requires energy (from low to high concentration)

1. Requires ATP

2. Transport proteins – move substances across the cell membrane

3. Endo/exocytosis – cell engulfs or “spits out” materials in vesicles

vi. Osmotic solutions

1. Definitions

a. Tonicity = difference in concentration between two solutions separated by a

semi-permeable membrane

b. Solute = solid; solvent = liquid

2. Types

a. Isotonic

i. Same amount of solute and solvent

ii. No net movement of water (water moves in & out at the same rate)

b. Hypertonic

i. High solute content; low solvent content (lots of “stuff”; not much

water)

ii. Net movement of water OUT of the cell (cell shrivels)

c. Hypotonic

i. Low solute content; high solvent content (not much “stuff”; lots of

water)

ii. Net movement of water INTO the cells

iii. Animal cells swell and burst (no cell wall to support)

iv. Plant cells display good turgor pressure

3. Cellular Energy (Photosynthesis and Aerobic Cellular Respiration)

a. How Do Cells Obtain Energy?

i. Thermodynamics – the study of the flow and transformation of energy

1. Energy is the ability to do work (ATP = adenosine tri phosphate)

a. Most important biological molecules for providing chemical energy

b. Releases energy when the bond between the second and third phosphates is

broken (ATP then becomes ADP)

2. 6 kinds of energy – radiant, thermal, chemical, mechanical, electrical, and nuclear

3. First law (conservation of energy) – energy cannot be created or destroyed, but it can be

converted from one form to another

4. Second law – when energy is converted, some usable energy is lost (entropy or disorder

increases)

ii. Types of organisms

1. Heterotrophs – must ingest food to get energy

2. Autotrophs – make their own food

a. Photosutotrophs – use sunlight

b. Chemoautotrophs – use chemicals

iii. ALL energy in living organisms originally comes from the sun (energy pyramid)

iv. Metabolism

1. A series of chemical reactions where the product of one reaction is the reactant for the

next

2. Two pathways (remember ABCD)

a. Anabolic: uses energy from catabolic pathways to BUILD larger molecules

(anabolic builds)

b. Catabolic: releases energy by breaking down large molecules into smaller ones

(catabolic destroys)

b. Photosynthesis

i. Performed by plants in the chloroplast

ii. Anabolic (uses sunlight to MAKE glucose)

iii. 6CO2 + 6H2O + sunlight C6H12O6 + 6O2

iv. Beginning of all food chains – so ALL life is supported by photosynthesis

v. Radiant energy from the sun is stored as chemical energy in the bonds of glucose

vi. What affects photosynthesis

1. Light intensity – the more light, the faster the rate of photosynthesis (to a point)

2. Carbon dioxide – the more CO2, the faster the rate of photosynthesis (to a point)

3. Temperature – if it is too high or too low, the rate drops

c. Cellular Respiration

i. Performed by ALL eukaryotes in the mitochondria

ii. Catabolic (breaks down glucose to release energy)

iii. C6H12O6 + 6O2 6H2O + 6CO2 + 36/38 ATP (energy)

iv. Four parts of aerobic respiration (aerobic = needs oxygen)

1. Glycolysis – splits glucose; makes 2 molecules of ATP

2. Kreb’s Cycle – makes 2 molecules of ATP

3. Electron Transport Chain (ETC) – makes 32-34 molecules of ATP

v. Anaerobic respiration (no oxygen present)

1. Starts with glycolysis – 2 molecules of ATP

2. Followed by fermentation – there are two kinds

a. Alcoholic Fermentation – occurs in plants and fungi (yeast)

i. Produces bread, beer, and wine

ii. Glucose broken down to make 2 ATP, 2 CO2, and 2 ethanol

b. Lactic Acid Fermentation – occurs in animals

i. Causes pain in muscles after a workout

ii. Makes 2 ATP and 2 lactic acid molecules

4. Cell Cycle and Mitosis

a. Cells divide so we can grow, repair damaged cells, and replace old cells (GRR – growth, repair, and

replacement)

b. Chromosomes

i. Most eukaryotes have 10-50 chromosomes, designated 2n (two times the number of

chromosomes we get from a parent)

1. For humans, 2n = 46

2. Diploid: 2n

3. Haploid: n

ii. Each chromosome is a single, tightly coiled DNA molecule wrapped around a protein called a

histone

iii. When DNA is loose it is called chromatin (like this during interphase, cytokinesis and resting).

When it is coiled, it is called a chromosome (like this during mitosis)

iv. Each chromosome is composed of 2 sister chromatids held together at their centromere

c. Cell division in prokaryotes (bacteria)

i. Call binary fission

ii. The single (circular) chromosome makes a copy of itself

iii. A cell wall forms between the 2 chromosomes, dividing the cell

d. Cell Cycle in eukaryotes

i. Interphase

1. G1 – first growth phase

a. Cells grow and mature – make more cytoplasm and organelles

b. Cell carries on normal metabolic activities

c. First checkpoint (restriction checkpoint) – cell decides whether to divide or go

into a resting phase (G0)

2. S – synthesis

a. DNA replicates (super important!!!)

3. G2 – second growth phase

a. Structures needed for division are made

b. Second checkpoint – cell checks for size and correct replication of DNA

ii. Mitosis – division of the nucleus (4 stages)

1. Prophase

a. Chromatin condenses into chromosomes

b. Spindle fibers form

c. Nuclear membrane breaks down

2. Metaphase

a. Spindle fibers attach to the centromere of the chromosomes

b. Chromosomes move to the equatorial plate (middle of cell)

3. Anaphase

a. Spindle fibers pulls sister chromatids to opposite ends of the cell

4. Telophase

a. Chromosomes decondense into chromatin

b. Spindle fibers disappear

c. Two new nuclear membranes form

iii. Cytokinesis

1. Division of the cytoplasm

2. Occurs after mitosis is complete

3. In animal cells, a cleavage furrow pinches in to split the cell in two

4. In plant cells, a cell plate forms at the equator to divide the cell

5. Daughter cells of mitosis: two genetically identical cells – same number of chromosomes

as each other and as the parent cell

e. Problems with mitosis

i. If cells do not rest (don’t enter G0), and stay in the cell cycle dividing uncontrolled, cancer occurs

ii. The result of unlimited cell division is an overwhelming number of immature “baby” cells that

crowd out normal cells – this group of immature cells is called a tumor

iii. Oncogenes – special proteins that increase the chance that a normal cell will develop into a

cancer cell

f. Cell Differentiation

i. All cells start as stem cells (undifferentiated)

ii. BUT different genes are turned on in different cells, causing the cell to specialize in its job

1. Can be caused by natural factors, like DNA and proteins

2. Can be caused by environmental factors, like chemicals, temperature, pH, etc.

iii. Examples

1. Animal Cells

a. Blood: carries oxygen to cells (RBC) and fights infection (WBC)

b. Muscle: allows movement (skeletal, smooth, cardiac)

c. Epithelium: skin, secreting mucus, & absorbing nutrients

2. Plant Cells

a. Root: absorb water and minerals from the soil

b. Stem: carry substances between roots and leaves

c. Leaves: capture sunlight and perform photosynthesis

d. Flowers: reproduction

5. DNA Structure/Replication

a. DNA Structure

i. History of DNA – 1950s

1. Rosalind Franklin used X rays to photograph DNA

2. Watson & Crick used the photograph to determine that DNA is a double helix

ii. Structure of DNA

1. DNA is made of nucleic acids, which are made up of nucleotides

2. Nucleotides – phosphate group, sugar (deoxyribose), and one of 4 nitrogen bases

3. Backbone is made of sugar and phosphate groups, connected by phosphate bonds. The

function is to provide the double helix structure and support

4. The middle is made of the nitrogen bases (adenine, thymine, guanine, and cytosine)

connected by hydrogen bonds

a. A always pairs with T (2 hydrogen bonds)

b. G always pairs with C (3 hydrogen bonds)

5. To fit into cells, DNA condenses by wrapping around histone proteins

6. The sequence of the nitrogen bases is what determines your traits and characteristics

iii. Gene Expression

1. Everyone has 46 chromosomes, or 23 pair, per person (23 from mom, 23 from dad)

2. ALL body (somatic) cells contain a complete copy of your ENTIRE genome(all your genes)

a. Gene = a segment of DNA that codes for a particular protein

b. Different genes are turned on in different cells

c. Therefore, different proteins are made by each cell – the cell only makes the

proteins necessary for it to do its job

d. This is a regulated process – proteins control which genes get turned on/off

3. ALL living organisms contain DNA, and the DNA for all is made out of the same things.

Only difference is the sequences of bases

b. DNA Replication

i. The enzyme helicase breaking the hydrogen bonds holding the nitrogen base pairs together

ii. The two sides of the DNA separate to be used as template strands

iii. The enzyme DNA polymerase adds new nitrogen bases to the template strands, which are

sealed together with the enzyme ligase

iv. End result is two identical pieces of DNA, each with one old strand (parent) and one new strand

(daughter); this kind of replication is known as semi-conservative

6. Protein Synthesis and Mutations

a. DNA mRNA protein

b. DNA is found in the nucleus, but protein synthesis occurs at the ribosomes

c. To get DNA out of the nucleus, it must be transcribed into RNA (ribonucleic acid)

i. RNA is single-stranded & contains the sugar ribose, a phosphate group, and four nitrogen bases

ii. The bases for RNA are guanine, cytosine, adenine, and URACIL (not thymine)

d. Types of RNA

i. Messenger RNA (mRNA) – copies the DNA code and carries the info from the nucleus to the

ribosomes

ii. Ribosomal RNA (rRNA) – makes up the ribosome (along with protein)

iii. Transfer RNA (tRNA) – transfers amino acids to the ribosome

e. Genetic Code

i. Ribosomes read the mRNA nucleotides in groups of 3 bases

ii. 3 bases = codon

iii. 20 amino acids, 64 codons (each amino acid may have more than one codon, but each codon

only codes for one amino acid)

1. Start codon – AUG (methionine)

2. Stop codons – UAA, UAG, or UGA

f. Steps of protein synthesis

i. Step One – Transcription (occurs in the nucleus)

1. Copying the sequence of one DNA strand (template strand) into mRNA

2. Requires RNA polymerase to separate the DNA strands and add RNA nucleotides (C, G,

A, or U) to match the DNA template (only one strand of the DNA is used)

3. Promoters are regions that show RNA polymerase where to begin

4. Termination signals – base sequences that tell RNA polymerase when to stop

5. After DNA is transcribed into RNA, it must be edited

a. Introns (non-functional segments) are taken out

b. Exons (coding segments) left in and attached together

6. mRNA leaves the nucleus through the nuclear pores and goes to the ribosome (floating

in cytoplasm or attached to rough ER)

ii. Step Two – Translation (occurs at the ribosome)

1. The process of decoding mRNA and turning it into a polypeptide chain (protein)

2. mRNA start codon (AUG) attaches to the ribosome

3. As the ribosome moves down the mRNA, tRNA brings over the correct amino acids

4. Peptide bonds attach the two amino acids together (protein = polypeptide)

5. End Product: A protein in its primary structure (string of amino acids bonded by peptide

bonds)

g. Mutations

i. Mutation means to change

ii. Substitution – one nucleotide is replaced with another

TAC CGC ACC TAT CAT CCA GTG

TAC CGC ACC TAT CAT CGA GTG

1. This is a type of point mutation (only affecting a single nucleotide)

2. Possible results

a. Silent: no change in the amino acid

b. Missense: get a different amino acid

c. Nonsense: get NO amino acid (STOP codon)

iii. Frameshift mutations

1. Causes changes in ALL codons that come after the mutation

2. Likely has a large impact since it changes the entire protein sequence

3. Examples

a. Deletion – a nucleotide is taken out completely

TAC CGC ACC TAT CAT CCA GTG

TAC CGC ACC TAT CT CCA GTG TAC CGC ACC TAT CTC CAG TG--

b. Insertion – an extra nucleotide is added to the sequence

TAC CGC ACC TAT CAT CCA GTG

TAC CGC ACC TAGT CAT CCA GTG TAC CGC ACC TAG TCA TCC AGT G----

iv. Chromosomal Mutations

1. Inversion: A section of a chromosome is removed, flipped, and put back

2. Translocation: a section of a chromosomes breaks off and attaches to a different

chromosome

v. Genetic wobble: when a change in the third base of a codon does not change the amino acid

(Ex: TAT and TAC both code for tyrosine)

vi. Impact of mutations on an individual depends on when and where the mutation occurs

7. Meiosis and Genetics

a. Meiosis – basis for sexual reproduction

i. Similar to mitosis, but division happens twice

ii. Results in 4 non-identical cells that each have ½ the amount of genetic information (n = haploid)

1. Start with one cell (called a germ cell) that has 46 double-stranded chromosomes (2n =

diploid)

2. After one division, you have 2 cells that each have 23 double stranded chromosomes

(n = haploid)

3. After the second division, you have 4 cells that each have 23 single stranded

chromosomes (n = haploid)

iii. For humans, these are egg and sperm cells (gametes)

iv. Starts with Interphase (just like mitosis), during which the cell grows and DNA doubles.

v. Occurs in 2 phases – Meiosis I and Meiosis II (this is known as reduction-division)

vi. Meiosis I

1. Prophase I – chromatin condenses into chromosomes and homologs pair up (called

tetrads), nuclear membrane breaks down, and spindle fibers form. Crossing over occurs

(pieces of chromosomes or genes are exchanged between the tetrads) to increase

genetic variation in offspring

2. Metaphase I – Spindle fibers attach to the double banded chromosomes and push them

to the middle of the cell (2 lines of homologous chromosomes)

3. Anaphase I – homologous chromosomes move apart to opposite poles (sister

chromatids remain attached at their centromeres)

4. Telophase I – two nuclear envelopes reassemble, the spindle fibers disappear, and

cytokinesis divides the cell in two

vii. Meiosis II

1. Prophase II – the nuclear membranes break down and spindle fibers form

2. Metaphase II – spindle fibers attach to the chromosomes and push them to the equator

of the cell

3. Anaphase II – Sister chromatids are ripped apart and moved to opposite poles

4. Telophase II – four new nuclear envelopes assemble, chromosomes de-condense, the

spindle fibers disappear, and cytokinesis divides both cells in two

viii. End Result

1. Gametes (sperm and egg)

2. 4 non-identical haploid cells with one copy of each chromosome (one allele of each gene)

b. DNA Technology

i. DNA Fingerprinting (DNA Typing)

1. A method of isolating and making images of DNA

2. Allows scientists to compare DNA sequences of different organisms and determine if

they are related

3. Used in criminal investigations and paternity testing

4. Process

a. DNA is collected; if there isn’t enough, you can perform PCR (polymerase chain

reaction) to make millions of copies of a single piece of DNA

b. DNA is then cut into pieces with restriction enzymes

i. Sticky ends – an overhang in DNA

ii. Blunt ends – straight cut across the 2 backbones

c. Pieces are placed a gel and subjected to an electric current

d. The current causes the pieces to move – the smaller pieces will move farther

than the larger pieces

e. Then the DNA can be “blotted” onto a piece of paper to make a picture

ii. Karyotyping (Chromosomal Analysis)

1. Karyotype = arrangement of homologous chromosomes from largest to smallest

a. First 22 PAIRS are the autosomes (regular chromosomes)

b. The 23rd pair are the sex chromosomes (XX = girl; XY = boy)

2. Only two things can be determined from a karyotype: the gender of the organism and if

they have any chromosomal mutations (usually caused by nondisjunction (failure of the

homologous chromosomes to separate properly)

a. Monosomy – only one copy of a chromosome (instead of 2)

b. Trisomy – three copies of a chromosome (instead of 2)

iii. DNA Transformation (genetic engineering)

1. Inserting fragments of DNA from an organism into another organism’s DNA

2. The fragment is carried into the other organism using a vector, usually a plasmid

3. Once the DNA from the two organisms is combined, it is called “recombinant DNA”

c. Genetics

i. Mendel

1. Austrian monk who studied inheritance in pea plants (called the “Father of Genetics”)

2. Developed the laws of inheritance

a. Law of Dominance: dominant alleles cover up recessive ones (heterozygous

individuals look dominant)

b. Law of Segregation: the two alleles for each trait separate into different gamete

cells during meiosis

c. Law of Independent Assortment: all alleles separate independently from each

other, which allows millions of different combinations of traits

ii. Terminology

1. Trait – any characteristic passed from parent to offspring

2. Heredity – passing of traits from parents to offspring

3. Genetics – the study of heredity

4. Genes – control the expression of traits

5. Alleles – two forms of a gene (can be dominant or recessive)

a. Dominant allele – the stronger of two alleles, covers up the recessive if present,

and is represented by a capital letter

b. Recessive allele – the weaker of two alleles that only shows up if the organism

has two copies, represented by a lowercase letter

6. Genotype – the genetic combination for a trait (the letters)

7. Phenotype – the physical feature resulting from the genotype (what the organism

LOOKS like)

8. Homozygous – have two of the same alleles (either two dominant or two recessive)

9. Heterozygous – have two different alleles; one dominant and one recessive; also called

a hybrid

10. Punnett Squares – used to held geneticists determine probable outcomes for offspring

iii. Mendelian Genetics

1. Monohybrid cross – a cross involving a single trait

• Example #1: Pea plant seed shape

Alleles: Dominant = round (R) Recessive = wrinkled (r)

Cross: Pure round seed X wrinkled seed

Genotype of offspring: 100% Rr

Phenotype of offspring: 100% round

• Example #2: Pea plant seed shape

Alleles: Dominant = round (R) Recessive = wrinkled (r)

Cross: heterozygous X heterozygous

Genotype of offspring: 25% RR, 50% Rr, 25% rr

Genotypic ratio: 1:2:1

Phenotype of offspring: 75% round, 25% wrinkled

Phenotypic ratio: 3:1

2. Dihybrid cross – a cross involving two traits

Example: Fruit fly body color and eye color

Alleles: Dominant = Black body (B) Recessive = Brown body (b)

Black eyes (R) Red eyes (r)

Cross: two organisms that are hybrid for BOTH traits (BbRr X BbRr)

Phenotypes: 9/16 Black body & Black eyes

3/16 Black body & red eyes

3/16 Brown body & black eyes

1/16 Brown body & red eyes

Phenotypic ratio: 9:3:3:1

iv. Non-Mendelian Genetics

1. Incomplete Dominance – the heterozygous organism will have a phenotype that is

between the two homozygous phenotypes

Example: Flower petal color

Dominant = red (R) Recessive = white (r)

Cross: heterozygous X heterozygous

Genotype of offspring: 25% RR, 50% Rr, 25% rr

Genotypic ratio: 1:2:1

Phenotype of offspring: 25% red; 50% pink; 25% white

Phenotypic ratio: 1:2:1

2. Co-dominance – both alleles for the gene exhibit equal dominance, therefore you see

both traits in the phenotype if they are present in the genotype

Example: blood type in humans

Dominant alleles = type A (IA) AND type B (IB)

Recessive allele = type O (i)

Genotype of offspring: 25% IAIB; 25% IBi; 25% IAi, 25% ii

Genotypic ratio: 1:1:1:1

Phenotypes of offspring: 25% type AB

25% type A

25% type B

25% type O

Phenotypic ratio: 1:1:1:1

8. Evolution

a. History

i. James Hutton – gradualism (gradual changes over time lead to species formation)

ii. Gould and Eldredge – punctuated equilibrium (a successful species remains unchanged;

environmental changes cause evolution to occur in spurts)

iii. Jean-Baptiste Lamark – law of use and disuse (organisms change size or shape of organs by using

them or not using them; adaptations are acquired during an organism’s lifetime)

iv. Charles Darwin – descent with modification (aka: natural selection) the organisms best adapted

for their environment will survive to reproduce and pass their adaptations on to their offspring

b. Evidence of evolution

i. Anatomical Homologies

1. Homologous structures – structural features with a common evolutionary origin

(example: a human arm and a bat wing)

2. Analogous structures – structures that perform a similar function, but have no shared

evolutionary origin (ex: the wings of a dragonfly versus the wings of a bird)

3. Vestigial structures – a body structure in a present-day organism that was useful in an

ancestor but is not useful to the individual (ex: appendix)

ii. Developmental Homologies (Embryology) - Embryos of fish, reptiles, birds, and mammals all

have a notochord, hollow dorsal nerve cord, post-anal tail, and pharyngeal gills

iii. Molecular Homologies (Biochemistry) – species with a more recent common ancestor have

similar hemoglobin amino acid sequences

iv. Biogeography – the study of how plants and animals are distributed on Earth

1. Similar environments lead to similar adaptations

2. Pangea – similar fossils found on different continents give evidence of tectonic plate

movement

3. Geographical barriers (mountains and rivers) cause physical separation and indicate

areas of different species

v. Fossil record – organisms are preserved as fossils when they are quickly buried in sediment

1. Law of superposition: the oldest rock (and therefore the oldest fossils) are at the bottom

strata (level), and the youngest rock (and more modern fossils) are near the top strata

c. Mechanisms of evolution

i. Genetic Drift: random change in allele frequency; causes a loss of genetic diversity/variation

ii. Gene flow: caused by migration (movement); increase genetic variation in the new population

iii. Natural Selection: Survival of the fittest – the ones best adapted to their environment will

survive and reproduce; can cause a loss of genetic diversity

1. Stabilizing – favors the average value

2. Directional – favors the beneficial trait (one of the extremes)

3. Disruptive – favors both extremes; eventually leads to two different species

iv. Mutations: random change in nucleotide bases; causes an increase in genetic diversity

d. Adaptations

i. Mimicry – one species resembles another species in order to trick predators into thinking it is a

more dangerous organism

ii. Camouflage – allows species to blend in with their environment

iii. Physiological adaptations – changes in an organisms metabolic processes (faster metabolism)

iv. Antibiotic resistance – some antibiotics developed during the 20th century are no longer

effective against bacteria

e. Speciation

i. Species: a group of organisms that can interbreed to produce fertile offspring

ii. Reproductive isolation – organisms of the same species no longer breed due to mechanical,

temporal, behavioral, habitat, or gametic issues, or offspring are non-fertile

iii. Genetic differences between the organisms increase and new species are formed

f. Cladograms

i. A branching diagram that shows the evolutionary history of a species

ii. The closer groups are on a cladogram, the more similarities they have, and the more recent

their common ancestor

9. Classification

a. Scientists give organisms scientific names to aid in organization and to avoid the confusion common

names cause

b. Scientific name = Genus species

c. Carolus Linnaeus – created the system of binomial nomenclature (2 part name)

d. Today, scientists classify organisms based on

i. Physical similarities

ii. Genetic similarities

iii. Biochemical similarities

iv. Behavioral similarities

e. Order of the 8 classification groups from broadest to most specific

i. Domain (Hemisphere)

ii. Kingdom (Continent)

iii. Phylum (Country)

iv. Class (State)

v. Order (City)

vi. Family (Neighborhood)

vii. Genus (Street)

viii. Species (House)

f. Mnemonic to remember the order of the groups: King Phillip Cried Out For Good Soup

g. 3 Domains

i. Archaea – prokaryotic, unicellular bacteria that live in extreme environments

ii. Bacteria – prokaryotic, unicellular, normal bacteria

iii. Eukarya – eukaryotic, often multicellular organisms

h. 6 Kingdoms – each has a set of characteristics that bind the organisms in that group together

i. Eubacteria

1. Prokaryotic (no nucleus or other membrane-bound organelles)

2. Unicellular

3. Most cannot make their own food (heterotrophic)

4. Decomposer – breaks down dead/decaying matter

5. Has cell walls (made of peptidoglycan)

ii. Archebacteria

1. Prokaryotic (no nucleus or other membrane-bound organelles)

2. Unicellular

3. Most digest chemicals not usable by other organisms (chemoautotrophs)

4. Found in “extreme” environments (lots of gas, super hot, very salty, etc)

iii. Protista

1. Eukaryotic

2. Some are unicellular, some are multicellular

3. Some are autotrophic, some are heterotrophic

4. Some have cell walls, others do not

5. The “odds-and-ends” kingdom organisms that simply don’t fit anywhere else

iv. Fungi

1. Eukaryotic

2. Multi-cellular (except for yeast)

3. Heterotrophic

4. Has cell walls made of chitin

5. Decomposer – breaks down dead/decaying matter

6. Can cause infections – athlete’s foot, ringworm, diaper rash

v. Plantae

1. Eukaryotic

2. Multi-cellular

3. Autotrophic

4. Has cell walls made of cellulose

5. Has a large central vacuole and chloroplasts (photosynthesis)

vi. Animalia

1. Eukaryotic

2. Multi-cellular

3. Heterotrophic

4. No cell walls

i. Dichotomous Key

i. Dichotomous – to divide in two

ii. A series of two choices, leading to the classification of an organism

10. Microbiology – Viruses and Bacteria

a. Viruses

i. Viruses are NOT alive!

ii. Virus = a non-cellular particle made of genetic material (DNA or RNA) surrounded by a protein

coat (capsid) with receptor proteins on the surface

iii. Only capable of reproducing when inside a host cell (otherwise they are inactive)

iv. Most viruses only infect specific host cells – only is their receptor proteins can fit on the proteins

of the host cell to trick the host cell into letting it inside

v. Bacteriophage – a virus that infects bacteria, has a tail with tail fibers to assist with attachment

to the bacterial cell wall

vi. Retrovirus – contains RNA instead of DNA, along with the enzyme reverse transcriptase

vii. Methods of infection

1. Lytic Cycle – take over cell function immediately (you get sick within a couple of days)

a. Attachment to the cell

b. Penetration/injection of viral DNA or RNA

c. Replication (biosynthesis) of new viral proteins and nucleic acids using host cell

machinery

d. Assembly (maturation) of new viruses

e. Release of new viruses into the environment (lysis of the cell)

2. Lysogenic Cycle – some viruses can lay dormant inside the cell for a time – up to years –

before activating in response to some external signal

a. Attachment to the cell

b. Penetration/injection of viral DNA or RNA

c. Phage DNA integrates into the host chromosome and lies dormant until

triggered by an outside signal

d. Replication (biosynthesis) of new viral proteins and nucleic acids using host cell

machinery

e. Assembly (maturation) of new viruses

f. Release of new viruses into the environment (lysis of the cell)

viii. Treatment

1. Antibiotic do NOT treat viruses (they target the cell walls or protein synthesis of

bacteria, neither of which exists in viruses since viruses aren’t cells)

2. If you get sick with a virus, usually the only thing to do is rest and drink plenty of fluids

3. Vaccines – giving a person a weakened or heat-killed virus to stimulate their immune

system into making antibodies against the virus to protect against future attack

ix. Specific types of viruses

1. Influenza

a. DNA virus

b. Lytic cycle

c. Transmitted via droplets of moisture (coughing/sneezing) or contact with a

contaminated objects

d. Must get vaccines every year because the receptor proteins mutate so rapidly

2. HIV

a. Retrovirus (RNA)

b. Lysogenic cycle

c. Transmitted via bodily fluids (blood, semen, vaginal secretions)

d. Attacks the T-cells of the immune system

11. Animal Systems

a. 12 organ systems

i. Skeletal – supports the body and protects organs (brain, kidneys, heart and lungs)

ii. Muscular – responsible for movement

iii. Integumentary (skin) – Protection against germs; prevents water loss; regulates body temp.

iv. Nervous – controls all mental and bodily functions; stimulus and response

v. Endocrine – releases hormones to keep the body at homeostasis

vi. Digestive – breaks down food so nutrients can be absorbed

vii. Excretory – eliminates wastes and excess water

viii. Immune – defends your body from germs and harmful, infection-causing organisms

ix. Lymphatic – returns fluid to the bloodstream and helps fight infections

x. Cardiovascular – blood carries oxygen, nutrients, and other materials to every cell in your body

xi. Respiratory – responsible for gas exchange (oxygen in, carbon dioxide out)

xii. Reproductive – produces male and female sex cells (gametes)

b. Specialized cells

i. Blood

1. Red blood cells (erythrocytes): carry oxygen to cells and carbon dioxide away from cells

2. White blood cells – disease fighters

ii. Neurons – transmit electrical signals throughout the body

iii. Muscle

1. Cardiac – involuntary beating of the heart

2. Skeletal – voluntary movement of the skeleton

3. Smooth – involuntary movement throughout body (digestion, childbirth, breathing…)

iv. Epithelium (skin) – protection, water retention, excretion (sweating)

12. Plant Structure and Function

a. Anatomy

i. Roots

1. Take in water and minerals from ground, which then enter the xylem

2. Anchor the plant into the ground

3. Storage of glucose

4. Root hairs – specialized dermal cells that increase the surface area of the root for more

efficient water/nutrient uptake

ii. Stems

1. Two-way transport – water up (through xylem), food down (through phloem)

2. Storage of glucose for the winter

iii. Leaves

1. Contain chloroplasts in the palisade layer that absorb sunlight (radiant energy) to

perform photosynthesis

2. Stomata (openings on underside of the leaf) allow gases (CO2 and O2) to move in & out

3. Opening and closing of the stomata regulated by guard cells

4. Cuticle – waxy covering on the leaf that helps prevent water loss (transpiration)

5. Absorbs sunlight (radiant energy)

iv. Vascular Tissue

1. Xylem: carries water and minerals up from roots to leaves

2. Phloem: carries glucose (food) from leaves to stem and roots for use and storage

v. Flower anatomy

1. Pistil/Carpel – female reproductive part; consists of the stigma (sticky tip), style (pollen

tube), and ovary (where the egg is found)

2. Stamen – male reproductive part; consists of the anther (where pollen is produced) and

filament (connects anther to plant); pollen = plant sperm

3. Petals – colorful part that attracts pollinators

4. Sepals – leaves that hold the petals up to attract pollinators

vi. Seeds and fruit

1. Ovary of the flower become the seed

2. Outer covering becomes the seed coat (the hard covering of the seed for protection)

3. When the ovary ripens, it forms a fruit around the seed (ex: a peach)

4. Seed dispersal – a seed that lands far from its parent has a better chance of survival

since there will be less competition for sunlight and water

a. Other organisms

b. Water

c. Wind

d. Ejection

5. Germination: when a plant pushes out of a seed

b. Tropism – a change in growth direction due to an external stimulus (regulated by the hormone auxin)

i. Geotropism – movement or growth is response to gravity (roots grow towards gravity, stems

grow away from gravity)

ii. Phototropism – movement or growth in response to light (a plant bending towards the light)

iii. Thigmotropism – movement or growth in response to touch (plants bend towards what is

touching them; in this way, vines wrap around tree trunks)

13. Ecology

a. The scientific study of the interactions between organisms and their environments (focusing on energy

transfer)

b. Two factors make up environments

i. Biotic factor –living organisms

ii. Abiotic factors – the non-living parts (temp, soil, water, light, air, etc)

c. Level of Organization (small to large): organism population community ecosystem biosphere

i. Organism – any unicellular or multi-cellular form exhibiting the characteristics of life

ii. Population – a group of organisms of one species living in the same place at the same time that

interbreed and produce fertile offspring. Compete with each other for resources

iii. Community – several interacting populations in a common environment

iv. Ecosystem – populations in a community and the abiotic factors with which they interact (also

called biomes)

v. Biosphere – life supporting portions of Earth composed of air, land, fresh water, and salt water

d. Habitat versus Niche

i. Habitat – the place in which an organism lives out its life

ii. Niche – the role a species plays in its community; its total way of life. Determined by the

tolerance limitations (limiting factors – any biotic or abiotic factor that restricts the existence of

an organism in a specific environment)

e. Ecological Succession – the natural, gradual changes in the types of species that live in a certain area

i. Primary

1. Begins in a place with no soil (ex: sides of volcanoes, landslides, flooding, new islands)

2. First lichens and moss grown on rocks, since they don’t need soil (pioneer species)

3. Lichens break down rocks into smaller pieces. When lichens die, they decompose and

add organic matter to the rock to make soil

4. Then grasses and weeds grow to hold the newly made soil (so no erosion)

5. When simple plants (grasses & weeds) die, they add more organic matter and nutrients

to the soil

6. Once the soil layer is thick enough wildflowers, shrubs, and trees

7. Ends with a climax community - a stable group of plants and animals that are the end

result of the succession process

ii. Secondary

1. Begins in a place that already has soil and was once the home of living organisms (after

natural disasters, like forest fires, tornados, etc.)

2. Occurs faster and has different pioneer species (grasses and weeds)

3. Ends with a reestablished climax community

f. Feeding Relationships Between Organisms

i. Producer-Consumer

1. Producer – all autotrophs (plants) that trap energy from the sun; bottom of food chain

2. Consumer – all heterotrophs that ingest food containing the sun’s energy (herbivores,

carnivores, omnivores, decomposers)

a. Primary – eat plants (herbivores)

b. Secondary, tertiary, etc – prey animals, carnivores

c. Decomposers – digest dead and/or decaying matter

ii. Predator-Prey

1. Predator: an organism that hunts and eats other organisms

2. Prey: an organism that is hunted and eaten

g. Symbiotic Relationships – a close and permanent association between organisms of different species

i. Commensalism – one species benefits, the other is neither harmed nor helped

ii. Parasitism – one species benefits (parasite) and the other is harmed (host), but not usually killed

iii. Mutualism – both species benefit

iv. Predation – one organism hunts and eats another

v. Competition – two organisms fight over the same resource(s) – food, water, living space, mates

h. Food Chains/Ecological Pyramids

i. Each link in the food chain is known as a trophic level (transfer of energy between levels)

ii. Biomass – total weight of LIVING matter at each trophic level

iii. Only about 10% of the energy gets transferred from one level to the next (the rest is used by the

organism or given off as heat)

iv. A food web shows all possible feeding relationships in a community at each trophic level (a

network on interconnected food chains)

14. Ecosystems/Biomes – groups of ecosystems with similar climates and organisms

a. Water Cycle

i. Water evaporates off the surface of the Earth (evaporation) or out of leaves (transpiration) as

water vapor

ii. Water vapor condenses into clouds (condensation)

iii. Droplets of water form from clouds and fall back down to the surface of the Earth (precipitation)

iv. Water that hits the earth moves to rivers/lakes/oceans (surface runoff) or is absorbed into the

soil (groundwater) and taken up by plants

b. Carbon Cycle

i. Autotrophs turn atmospheric carbon (CO2) into glucose (C6H12O6)

ii. Heterotrophs eat the autotrophs or other animals that ate the autotrophs to get the glucose;

they also release CO2 into the air as a product of cellular respiration

iii. When organisms die and decompose, their carbon is put into carbon reservoirs in the ground

(fossil fuels)

iv. Fossil fuels are dug up and burned, which releases CO2 into the atmosphere. Excess CO2 into the

atmosphere, which leads to the “greenhouse effect” (warming of the Earth)

c. Nitrogen Cycle

i. 78% of the air is nitrogen, but it is not in a form plants can use

ii. Nitrogen-fixing bacteria “fix” atmospheric nitrogen into organic nitrogen which is found in soil

iii. Organic nitrogen is turned into ammonia (ammonification)

iv. Ammonia is turned into nitrate (nitrification), which can be absorbed by plants into their roots

v. Nitrate can be turned back into atmospheric nitrogen (denitrification)

d. Population Dynamics

i. Population Density – the number of organisms in a given area

ii. Tolerance – the ability of an organism to survive in the ecosystem

iii. Limiting factor – any biotic or abiotic factor that restricts the numbers, reproduction, or

distribution of the organisms

iv. Carrying capacity – the maximum number of individuals of a species that an environment can

support long-term

v. Biodiversity – the variety of life in an area; the higher the biodiversity, the healthier and more

stable the ecosystem

e. Environmental Change

i. Climate change – an area’s average weather conditions are affected by latitude, elevation, wind,

and ocean currents

ii. Acid precipitation – caused by the burning of fossil fuels; removes nutrients from the soil and

damages plants

iii. Deforestation – forests chopped down (usually for logging or burning); caused decreased

biodiversity, release of greenhouse gases (CO2), disrupted water cycle, & increased soil erosion

iv. Eutrophication – over-fertilization of crops causes increased runoff of excess nitrogen into rivers

and lakes, which causes an overproduction of algae (algal blooms), which block the sun and

cause “dead zones” in the water, where no fish or sea life can live