First semester Study GUIDE This study guide is designed to reinforce your knowledge of biology. This study guide

can be used with your practice END OF COURSE (EOC) tests.

- Please use the space below to write any questions you have over the practice EOC test or the study guide. If you need help on a specific question or topic, please write your concerns down. This is given to you as an aid and should be used. I’m just trying to give you everything you need to be successful.

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- Biology Process • Demonstrate knowledge of inquiry techniques

- Questions that will come from these will look a lot like the questions from the ACT practice we have been doing. You need to feel comfortable reading data from charts and graphs. Questions will also see if you completely understand the scientific process.

o The scientific process: Observation- observing of the natural world or phenomenon that has taken

place Question- Form question about the observation. Hypothesis- Making an explanation about an observation (your educated

guess). Experiment- Conduct an experiment

Experiment should be controlled meaning only one variable should change. Should be done more than once to ensure accuracy.

o Manipulated variable (Independent Variable)- The variable you change on purpose

o Responding variable (Dependent Variable)- Variable that changes during the experiment due to the manipulated variable

o Controlled variable – Variables that stay the same. Record data- Record data in graphs or tables Form a conclusion- based on your experimental results produce a conclusion

from the question. (what did you learn from the results.) - Questions on the EOC test will give you simulated experiments and ask you to find the

problems within the scientific process, whether it be an experiment that is wrong or identify the different variables.

• Use mathematics and measurement; use graphical and mathematical models

- Questions from this area will ask you to read data from graphs, charts and passages.

• Identify criteria necessary to characterize life; define biological organization levels

- Questions from this topic will include understanding of characteristics of life and biological organization.

o Characteristics of life include: Living things are made up of units called cells. Living things reproduce Living things are based on a universal genetic code

Living things grow and develop Living things obtain and use materials and energy Living things respond to their environment Taken as group living things change over time (evolve)

o Biological organization -Remember BIO means living Cells Tissue Organs Organ systems organism

- Biochemistry; Cell • Describe atomic structure, bonding between atoms, organic and inorganic compounds,

Enzymes, and ATP

- Atomic structure- atoms are composed of neutrons, protons, electrons

o Protons- Positively charged; located in the nucleuso Neutrons- NO CHARGE; located in the nucleuso Electrons- Negative charge; located in clouds/shells outside the nucleus

Valence electrons- electrons in the outer-most shell

Octet rule- All ATOMS strive to have 8 (OCT) electrons in their outer most shell/ except the first shell which can contain 2.

- Bonding between atoms -can occur two MAIN ways; Covalent bonding, and Ionic bondingo Covalent bonding

Occurs when two atoms share electrons- Hence the CO =cooperative Keep in mind the octet rule from above. Atoms strive to reach 8 valence

electrons. EX. Water= H2O. Hydrogen has 1 electron in its first shell and only needs one more. Oxygen has 6 valence electrons and only needs two to achieve the octet. Therefore it takes two hydrogen sharing two different electrons to equal a total of 8 for the Oxygen and each hydrogen atom is sharing 2 electrons with the oxygen.

o Ionic bonding Ionic bonds occur when atoms give away or take electrons to obtain

the octet rule. When atoms give away electrons, they change to a net positive charge.

When atoms take an electron, they change to a net negative charge.

- Organic compounds- are compounds that are formed of carbon chains (C-C-C-C) and are extremely important to life. There are four main organic compound groups: Carbohydrates, Lipids, Proteins, and Nucleic Acids. All four of these organic compounds are made from the following elements: sulfur, phosphorus, oxygen, nitrogen, carbon, hydrogen (SPONCH)

o Carbohydrates- are sugar molecules and are the compound we living things get our energy from. We take in Carbohydrates break them down in the presence of oxygen, to release the energy they have. There are different types of Cabohydrates:

Simple carbohydrates (sugars)- These carbohydrates are formed from one single sugar molecule and include glucose, fructose. Anything ending in OSE is a carbohydrate.

Complex carbohydrates- These carbohydrates are formed from two or more single sugar molecules bonding together to form large chains of single sugars. An example of these would include: Starch, Chitin, and Cellulose.

o Lipids- Are large carbon based compounds that living things use to store energy. They include fats oils waxes and steroids. These molecules are hydrophobic (water hating), which means they do not dissolve in water. This is why they can be found in the cell membrane. The lipids in the cells membrane water-proof our cells.

o Proteins- Proteins can arguably be the most important organic molecule. Think about it, DNA is housed in a protective covering called the nucleus, and never leaves that protection. DNA contains the information for our cells to build proteins.

Proteins can be structural which means they build important structures of our body. They can also be functional, which means they regulate a lot of the chemical processes that occur in the body.

o Nucleic acids- These organic molecules are the building blocks for our DNA, they build structure called nucleotides, which are the sub-units or DNA.

DNA- is the genetic material of our bodies. It is responsible for holding all the information for all cellular activities. DNA is also the molecule that allows us to pass on our genetic information to our children.

DNA structure- DNA is a huge molecule that takes the shape of a double helix (twisted ladder).

DNA is made up of subunits called nucleotides with consist of a phosphate backbone (sides of ladder), 5 carbon sugar (Deoxyribose), and a nitrogenous base. DNA consists of only 4 different nitrogen bases; Adenine, Thymine, Adenine, Guanine. (AT, CG)

These bases pair up in a certain way; A-T, G-C On a side note DNA and RNA are closely related, but different in a

few ways: o DNA is double stranded, RNA is single strandedo DNA contains the nitrogenous bas of Thymine, RNA replaces

Thymine with Uracil.o DNA never leaves the nucleus; RNA leaves the nucleus

carrying with it the information to build proteins.

- Inorganic molecules- Molecules that do not have a carbon backbone. EX. FeO (Iron Oxide), NaCl (table salt).

- Enzymes- Are specialized proteins that speed up chemical reactions in living things. Anything ending in ASE can be considered an enzyme. An example would be LACTASE, which is the specific enzyme that acts on LACTOSE, The sugar found in Dairy products. People who are Lactose intolerant Lack the enzyme LACTASE which allows for the breakdown of this sugar. Since DNA codes for proteins, and people that are lactose intolerant lack the enzyme Lactase (a protein), it can be traced back to a problem with their DNA.

- ATP- Is a chemical compound that has the ability to store small amounts of energy. ATP is produced from glucose in the presence of oxygen in the mitochondria. Glucose is also an energy containing molecule. Glucose contains way too much energy for our cells to use directly, so our cells go through a process called cellular respiration to produce ATP which contains less energy. One molecule of glucose is equal to 38 ATP. Now that energy has been contained in ATP, the cell uses it for all cellular activities. Anything the cell does that requires energy uses ATP.

o Structure of ATP- ATP is Adenosine triphosphate. The TRI in front of phosphate means there are three phosphate molecules attached. These three phosphates are very important, because the energy all of our cells use is stored in the last phosphate to phosphate bond (P-P). When that bond is broken, it releases the energy. After the energy is released ATP turns into ADP. Because the release of energy caused the 3rd phosphate to be broken off Adenosine Triphosphate (3 Phosphates), the molecule is now called ADP= Adenosine Diphosphate (Di meaning 2 phosphate). ADP can and is recycled back into ATP by attaching another phosphate, which requires energy. This energy comes from the energy carrying molecule glucose.

• Explain properties of water and describe pH of a solution

- Questions from this area will test your understanding of water and its properties. You will also be tested on your ability to understand the PH scale

o Properties of water- Water is formed when two hydrogen atoms combine with one oxygen atom. This chemical reaction takes a lot of energy to get started, that is why all the hydrogen and oxygen in the atmosphere doesn’t combine and form water. \

Water is a polar molecule which is its most important property. Water is polar, since it has an uneven distribution of electrons. There are more electrons surrounding the oxygen, giving that area a net negative charge. And the area around the hydrogen a net positive charge. Thus, a water molecule acts like a magnet with a + and – end. This is what gives water molecules the ability to stick to each other.

Water being a polar molecule also allows it to dissolve a lot of other compounds.

o The PH scale- The PH scale is a numerical scale going from 1 to 14, and 7 being neutral (pure water). Measures the strength of acids and bases.

The lower the number the more acidic a solution is. As the number goes lower from 7 more H+ ions get produced in the solution making it a stronger acid.

As the number gets higher from 7 the more basic the solution. As the solution gets more basic there are more OH- ions (hydroxide ions) produced.

More H+ ions than OH- ions the solution is acidic. The greater the difference the stronger the acid

More OH- ions than H+ ions the solution is basic. The greater the difference the stronger the base.

• Identify cell types and describe functions of cellular organelles

- Questions from this area will test your knowledge of cells and cell structure. o There are two main types of cells:

Prokaryotic cells- have no nucleus These types of cells include Bacteria

Eukaryotic cells- These types of cells contain a nucleus and other membrane enclosed organelles. Two main types of Eukaryotic cells are plant and animal cells.

o Eukaryotic/animal cell structure (Organelles) Nucleus- is a membrane enclosed structure that

contains and protects DNA. Ribosomes are made in a dense region of the nucleus called the nucleolus. It

contains pores, which are openings. These pores are there for mRNA to carry information from DNA outside the nucleus. DNA never leaves the nucleus. On a side note, DNA can also be found in the mitochondria of eukaryotic cells.

Cell membrane- is a double layer (bi-layer) surrounding the entire cell. The cell membrane monitors what enters and leaves the cell. It is the bouncer. This layer is made up of a phospholipid bi-layer, and can be called the phospholipid bi-layer as well.

Mitochondria- A membrane enclosed organelle that produces energy in the form of ATP for the cell. ATP is the energy type that all cells use for all cellular activities. Because our muscle cells use lots of energy, they contain more mitochondria than other cells in the human body. Mitochondria are the site where the oxygen we breathe and glucose (sugar/ carbohydrates) we eat meet, and the energy in glucose is transformed through a process called cellular respiration into ATP. We exhale the byproducts of Carbon dioxide (CO2), water vapor (H20), and heat. (That’s the reason you can fog up a window. )

Ribosomes- These tiny organelles are the site of protein production. DNA contains the information to make specific proteins; mRNA is made in the nucleus, through a process called translation, and carried out of the nucleus through nuclear pores. mRNA now carries the information to make proteins to a ribosome where a process called transcription builds a protein your body needs.

Endoplasmic reticulum- Is a membrane enclosed organelle that creates passage ways throughout the cell. The rough ER has ribosomes attached and helps aid in protein production. The smooth ER aids in lipid production.

Golgi Apparatus- When proteins are made in the rough ER or on free floating ribosomes, they are sent to the golgi apparatus. This organelle modifies, and encloses the protein in a vesicle (bubble), then ships the protein to where it is needed. The Golgi apparatus can be looked at as the UPS of the cell; it modifies, and ships packages of proteins.

Vacuole- A membrane enclosed organelle, which stores carbohydrates (sugars), Lipids (fats), and proteins.

o Plant cells- Are cells that make up the structure of plants. Plant cells have all the listed organelles of animal cells with a few added: Chloroplast, Large central vacuole, cell wall.

Chloroplasts- Specialized organelle only found in plant cells. Is the location of photosynthesis. Contains the pigment chlorophyll, which makes the plants green.

Photosynthesis- The process of capturing light energy and using that energy to convert Carbon Dioxide (CO2) and Water (H2O) into glucose (C6H12O6) and Oxygen (O2). The chemical equation for photosynthesis is 6CO2 + 6H2O C6H12O6 + 6O2 + ENERGY. So basically photosynthesis takes energy from the sun and stores it in a molecule of glucose.

• Describe movement of substances into and out of cells

- This area of the test will test your knowledge of the following processes, which allow substances to pass through or out of the cell membrane: Diffusion, Osmosis, Active transport, passive transport, endocytosis, and exocytosis. All these processes take place on our cell membranes because they are semipermeable. Semipermeable means small things can pass through and larger things can’t pass through.

o Diffusion- Is the movement of particles (molecules) from high concentration from low concentration. This movement from high concentration to low concentration is called the concentration gradient). Ex. Spray perfume into the air and the scent (molecules) will spread (diffuse) throughout the room, from the area you sprayed (high concentration) to areas it is not located (low concentration). The particles (molecules) of scent will continue to diffuse and move throughout the room until it reaches an equilibrium. Equilibrium means all molecules are spread out equally.

o Osmosis- Is simply the diffusion of water. Some molecules are too large to diffuse across a membrane (cell membrane). When this happens water will dissolve through the membrane until an equal concentration is reached on both sides (equilibrium).

There are three types of solutions when dealing with osmosis: Hypotonic, isotonic, and hypertonic.

Hypotonic- Hypo means below. So the solution is less concentrated than the cell placed in it. To equal out the concentrations of the cell and the solution, water rushes in and causes the cell to swell. The cells will swell until it bursts or equilibrium is reached. This is why it is not a good idea to drink distilled water. Distilled water is hypotonic compared to our red blood cells. The hypotonic distilled water causes water to rush into our cells and causes our cells to swell. A woman died a few years ago trying to win a water drinking contest. The contest stated; whoever drinks the most water wins a xbox. The people putting on the contest never thought about osmosis and had the contestants drink distilled water. The woman who died drank so much of the distilled water her red blood cells swelled and bursts, which lead to a stroke.

Isotonic- Iso means equal. So this means that the solution has the same concentration as the cell placed in the solution. Water does not rush in and the cell placed in the isotonic solution stays the same size. An example of an isotonic solution is IV fluids. Hospitals us IV fluids to hydrate patients. Because the IV is isotonic it doesn’t cause cells to swell/burst or shrink.

Hypertonic- Hyper means above. So the solution the cell is placed in has a higher concentration the cell itself. To equal out this concentration water rushes out of the cell, trying to water down the highly concentrated solution it is placed in. This is the exact reason humans can’t drink saltwater. The saltwater is hypertonic, and causes our cells to lose water, which dehydrates use even further.

Passive transport- This is the category of transport that doesn’t require energy from the cell. These types of transport rely on the principles of physics. Diffusion and osmosis are both types of passive transport.

Active transport- This is a category of transport that requires energy from our cells, in the form of ATP, to move things across the cell membrane. These types of transport include; Protein pump mediated transport, endocytosis, and exocytosis.

o Protein pump mediated transport- This type of transport across the cell membrane relies on a protein pump, which acts like a door way or a gate into the cell. It takes energy to work this pump (doorway). These protein mediated pumps bring in molecules that are too large to diffuse across the membrane or they can pump things across the concentration gradient (From low concentration to high concentration).

o Endocytosis- is the process of bringing things into the cell by folding the cell membrane and creating a pocket. There are two types of endocytosis; Pinocytosis, phagocytosis.

Pinocytosis- the process of bringing in liquid. The name pinocytosis literally means cell drinking.

Phagocytosis- The process of bringing in solids. The name literally means cell eating.

o Exocytosis- The process of releasing materials through vesicles (bubbles) forming with the cell membrane.

• Describe cellular respiration.

- During this portion of the test you will be tested on your knowledge of cellular respiration. o Cellular respiration -is the process of living things taking in oxygen and glucose to

produce energy in the form of ATP. Cellular respiration can be broken down into smaller processes. What you need to keep in mind that all living things are chemical factories, we are constantly taking in molecules and breaking them down and building new molecules. Every second there are thousands of chemical reactions taking place in your body, which break down molecules into smaller ones and then building new molecules. Cellular respiration is a process and can be divided into different stages; Glycolysis, Krebs cycle also called the citric acid cycle, and the electron transport chain. The steps in which your body creates ATP (energy), when oxygen is present is 1. Glycolysis, Krebs cycle, electron transport chain. When oxygen is present it is called aerobic respiration. The starting materials for these processes are oxygen and glucose, which we inhale and consume with food. The chemical equation for cellular respiration is: C6H12O6+ 6O2 Energy+ 6CO2+ 6H2O.

Glycolysis- beginning step in cellular respiration, and creates 2 ATP molecules and also creates the substances required for the Krebs cycle.

The Krebs cycle- Begins when glycolysis ends and creates 2 more ATP. Krebs cycle also creates free electrons, which are needed during the Next step; Electron transport chain.

Electron transport chain- is the final stage of cellular respiration, and creates 34 ATP.

o Anaerobic respiration- When Oxygen is absence (anaerobic respiration), like when you get out of breath, living things can still convert glucose into ATP through process call Lactic acid fermentation. Although we can create energy without oxygen we can only do it for a short period of time. Lactic acid fermentation creates ATP and lactic acid. This process happens in humans when we get out of breath. The lactic acid formed from this is stored in our muscles in a crystal form (sharp edges). These lactic acid crystals rip and tear our muscles and cause us to become sore.

• Describe cell division and mitosis

- Questions from this part of the test will test your knowledge on Cell divisiono When looking at cell division, we need to understand the cell cycle. The cell cycle is

the life stages of a cell. Just like we go through life stages (infancy, child, preteen, teen, adult), a cell goes through life stages as well. The stages of the cell cycle in order are as follow; G1, S, G2, mitosis, cytokinesis. The g1, S, G2 phases are combined and called Interphase.

G1- Is the Growth phase. The cell grows and prepares to copy the DNA. S- The S phase is when DNA is replicated. It is very important to replicate the

DNA of a cell. A human cell has 46 individual chromosomes, if the s phase doesn’t happen the resulting 2 daughter cells will only have half the DNA needed and the cell will die. So in human cells the s phase will cause 46 individual chromosomes to double into 92.

DNA replication- the process involving DNA polymerase (unzips and unwinds DNA and build back the corresponding sides) the copies the DNA molecule.

G2- The g2 phase is the phase when the cell continues to grow and mature. Mitosis- Mitosis is defined as the dividing of the nucleus only. NOT THE

SPLITTING OF THE CELL. Mitosis occurs in our somatic cells, which are all our body cells. Mitosis take place in every cell we have, except our sex cells

(sperm and egg). Mitosis can be broken down into different phases. In order the phases of mitosis are: prophase, metaphase, anaphase, telophase. A good way to remember the sequence is to remember PMAT.

Prophase- The Loosely wound DNA tightens up on proteins called histones, to form tightly wound packages of dense genetic material called chromosomes. The nucleus also starts to break apart.

Metaphase- Is the phase at which all the chromosomes line up at the equator (middle) of the cell. Once all the chromosomes are lined up metaphase is over.

Anaphase- Is the phase in which the chromosomes are pulled apart toward each end of the cell. Each side of the cell will get a full and complete copy of genetic material. In humans 92 chromosomes line up and each side of the cell will get 46 (a complete set). Anaphase is over when each side of the cell receives the chromosomes.

Telophase- is the process of the nuclei (plural for nucleus) starts to reform. During this phase each area of DNA will be enclosed by a new nuclear membrane.

Cytokinesis- Takes place at the same time as telophase. Cytokinesis is the actual splitting of the cell.

Cytokinesis in plant cells doesn’t involve the pinching of the two plant cells, but the formation of a cell plate (new cell wall) between the two new nuclei.

Once all these steps have been accomplished, the cell cycle starts back over at the G1 phase.

-Genetics; Evolution• Describe basic structure and function of DNA, RNA, and proteins

- Questions from this part of the test will test your knowledge on how DNA can be translated into RNA and the process of RNA Transcribing into a protein.

o First, A few important things we should understand at this point: DNA is made up of sub-units called nucleotides. These nucleotides arrange themselves into a structure called Double helix DNA is located in the nucleus. A protein is a chain of Amino Acids held together by polypeptide bonds.

Proteins can be huge, hundreds of amino acids long. Ribosomes are the site of ribosome production.

o DNA structure- Made up of sub-units called nucleotides. These nucleotides are made up of

even smaller units: Phosphate group, Deoxyribose (5-Carbon sugar), and a nitrogenous base.

NUCLEOTIDE

The actual double helix structure of DNA occurs when these nucleotides attach to each other, as shown below.

In a DNA molecule the phosphorus group and the deoxyribose group (S) are the actual sides of the molecule.

The nitrogenous bases are the bases that make up the runs of the twisted ladder shape.

o There are four nitrogenous bases: Adenine, Thymine, Guanine, and Cytosine. These bases only pare up a certain way. Adenine with Thymine, and Guanine with Cytosine.

DNA can make copies of its self in a process called replication, which takes place in the nucleus with the help of an enzyme called DNA polymerase.

o RNA structure- RNA is a molecule that is closely related to DNA with only a few key differences. The differences are as follows:

RNA is single stranded RNA replaces Thymine with Uracil RNA can leave the nucleus.

There are three main types of RNA: mRNA- The RNA that leaves the nucleus, carrying with it

the information to build a protein. The mRNA is created in the nucleus through a process called transcription. mRNA then leaves and attaches itself to a ribosome.

tRNA- This RNA molecule is attached to an amino acid. tRNA lines up with mRNA from the nucleus and attaches its amino acid to the one before it. As more molecules of tRNA line up with the mRNA a chain of amino acids form, this is a protein. Remember a protein is a chain of amino acids linked together. This process of tRNA lining up with mRNA and creating the protein is called translation.

o Differences between mRNA and tRNA are simple. mRNA is a longer molecule. tRNA is short and has an attached amino acid.

rRNA- The ribosome organelle is actually made from an RNA molecule. And this molecule of RNA that makes the ribosome is called rRNA.

o Protein structure- Are made from information stored in DNA. That information leaves the nucleus in the form of mRNA and attaches to a ribosome, where tRNA attaches amino acids together to form a long chain of amino acids called a protein.

Proteins are a chain of amino acids help together by polypeptide bonds. Proteins can wind and form very complex structures.

• Describe meiosis

- Meiosis is the process of one germ cell, going through 2 divisions, and creating 4 gametes (sex cells). This division is a reduction division which means the resulting daughter cells will have less genetic material than the starting germ cell. This type of division only takes place in the formation of gametes. The process of meiosis can be divided into 2 major divisions: Meiosis 1 and Meiosis 2.

o Meiosis 1 – The first division. DNA has already been duplicated. In humans 46 has been doubled to 92 total chromosomes. The first division results in 2 daughter cells that contain 46 total chromosomes in humans. The first division is almost identical to mitosis. The cell goes through prophase, metaphase, anaphase, telophase. And cytokinesis. The main difference between meiosis 1 and mitosis is, during metaphase of meiosis 1 crossing over occurs. Crossing over is the process of exchanging DNA on homologous chromosome. Remember you have two copies of every chromosome (One copy from each parent). The two chromosomes you have for a given pair are called homologous (Homo = same). So during crossing over the genetic information you have on one homologous pair is shuffled like a deck of cards. This crossing over results in greater genetic variety.

o Meiosis 2- Starts directly after cytokinesis of meiosis 1. It too goes through the same phases: Prophase, Metaphase, Anaphase, Telophase, and cytokinesis. The main thing to remember is meiosis 2 is the dividing of two cells with 46 chromosomes into 4 cells with 23 chromosomes (in humans). Each of the four resulting cells contains exactly 1 copy of each chromosome.

Diploid (Di = 2)- a cell that contains 2 copies of every chromosome. Haploid (Hap = Half) - A cell that contains 1 copy of every chromosome.

Contains half the genetic information. o Meiosis starts with one diploid cell and ends with 4 genetically different haploid sex

cells. The sex cells will unite during sexual reproduction and create one diploid cell with all the information to form a multicellular organism (human). You were once one single cell caused by the uniting of two haploid cells, and the resulting single diploid cell divided through mitosis to create you, and as an adult you will have over 50 trillion individual cells.

• Use correct terminology when working with genetic crosses

- This area of the test will test your knowledge of Punnett Squares and the terminology that goes with it. When doing genetic crosses you need to understand that some traits exhibit different characteristics than others. Some traits are simply dominant or recessive; others are incomplete dominant and co-dominant. It is also very important to remember sex-linked genes. These are genes that are found on the sex chromosomes (XY). The following terms are those you need to understand to perform Genetic crosses. While reading these definitions and looking at the example Punnett Square, you should know the following: Most traits are controlled by 2 genes, one from your mother and one from your father. You have two copies of each gene. The physical trait showed through gene expression depends on the types of alleles you have. Ex. (If you have one dominant and one recessive the trait shown will be the dominant. If you have two recessive alleles the trait shown will be the recessive trait. )

o Gene- a segment of DNA that codes for a specific protein, the protein which is made will produce the desired characteristic.

o Allele- Every characteristic has multiple possibilities, for example eye color in humans has several variations. These different gene types are called alleles. The definition for allele is different variations of the same gene.

o Dominant gene- Is a gene / trait that is represented with an upper case letter (T). This trait will always show its characteristics over recessive traits.

o Recessive trait- Is a gene / trait that is represented with a lower case letter (t). This trait will only show its characteristic if there is an absence of the dominant trait.

o Co-dominant trait- Both genes controlling the trait are dominant. The results of a co-dominant trait show both characteristics of each gene. Ex. A dominant white allele + a dominant black allele will result in a spotted of speckled black and white trait.

o Sex-linked genes- Are genes found on the X or Y chromosome. Because these sex linked chromosomes get separated differently during meiosis, they show different results when doing a genetic cross. The male of the species contains only one X chromosome and a single Y chromosome. Since the male only contains one X whatever allele is on the X chromosome will show. Autosomes are chromosomes that are not sex chromosomes.

o Incomplete dominance- Is when neither allele is completely dominant over the other and it results is a mix of the two genes. Ex. Dominant white allele+ Dominant red allele will result in a pink, which is a blending of the two genes.

Genotype- Is a term used to describe the types of genes present. There are 3 different genotypes: Homozygous dominant, homozygous recessive, and Heterozygous.

Homozygous Dominant- Remember that the prefix homo means the same. Homozygous dominant means there are two dominant alleles present. Ex. (TT)

Homozygous recessive- Means there are two recessive alleles present. Ex. (tt)

Heterozygous- Hetero literally means different. Heterozygous means 2 different alleles, one dominant and one recessive. Ex. (Tt)

o Phenotype- Is a word used to describe the physical characteristic of a gene.

o An example of a Punnett square.

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