reporting category 2 organization of living systems
TRANSCRIPT
Reporting Category 2
Organization of Living Systems
TEK 6A Identify components of DNA, and describe
how information for specifying the traits of an organism is carried in the DNA
General Information Purpose: Genetic information is stored in DNA Location: nucleus of living cells Discovery: Watson and Crick discovered the
3D shape of DNA, now called the Double Helix Structure:
Sugar phosphate backbone Nucleotides (nitrogenous bases)
Matching and Bonding Matching base pairs:
A-T C-G
Bonds that hold DNA together: Backbone: connected by
covalent bonds Bases: connected by hydrogen
bonds
Example Questions1. Why will knowledge of the human genome enable scientists to better understand proteins involved in human diseases?A: DNA contains the information used to make proteins
2. A particular strand of DNA has the base sequence ATT-CCG. What is the base sequence of the complimentary strand?A:TAA-GGC
TEK 6E Identify and illustrate changes in DNA and evaluate the significance of these changes
What causes mutations?1. DNA damage from environmental
agents such as ultraviolet light(sunshine), nuclear radiation or certain chemicals
2. Mistakes that occur when a cell copies its DNA in preparation for cell division
Types of Mutations1. Point mutation-change to one base in a gene
sequence
2. Inversion- an entire section of DNA is reversed
Types of Mutations3. Frame shift- one or more bases are inserted
or deleted, like adding or removing letters in a sentence
a. insertion-adding one or more bases to a gene sequence
b. deletion-when one or more bases to a gene sequence are deleted (or missing)
Example Question
TEK 6FPredict possible outcomes of various genetic combinations such as monohybrid crosses, dihybrid crosses and Non-Mendelian inheritance
Important Vocabulary Dominant- an allele that is expressed or
shown in the phenotype; it masks or hides recessive allele traits
Recessive- an allele that is not expressed or shown in the phenotype because it is hidden by the dominant allele
Homozygous- when an organism has the same alleles for a trait (can be dominant or recessive)
Heterozygous- when an organism has two different alleles for the same trait (dominant trait is shown)
Genotype vs. Phenotype
Genotype Phenotype Refers to the two
alleles an individual has for a specific trait
Refers to the physical appearance of the individual
Mendelian vs. Non-Mendelian Genetics
Mendelian Non-Mendelian Law of
Segregation Each individual
has a pair of alleles for each trait
Alleles segregate during gamete formation(egg and sperm)
Fertilization gives the offspring two alleles
Incomplete dominance If an organism is
heterozygous for a trait the phenotype is a blend of the two allele types
Codominance An organism that
has both alleles of a gene displays both phenotypes at the same time
Examples of Non-Mendelian Genetics
Monohybrid and Dihybrid crosses
Monohybrid Dihybrid After completing the
punnett square answer the questions
1. what percent of the offspring will be short?
2. what percent will be tall?
What is the genotypic ratio for DdRr?
More Dihybrid Practice: AABb x AaBb
TEK 6B Recognize that components that make up
the genetic code are common to all organisms
The Genetic Code In all living organisms, the
instructions for reproducing and operating the individual is encoded in DNA
The genetic code is universal This leads scientists to believe
organisms have a common ancestor
The Genetic Code How many different
codons code for Leucine (Leu)?
6 What does that lead
you to believe about the genetic code and mutations to DNA?
That if one base pair changes, the mutation may have no effect if you still end up with the same amino acid
TEK 6C Explain the purpose and process of
transcription and translation using models of DNA and RNA
Central Dogma Thesis that information flows from DNA to
RNA to protein
Protein Synthesis Protein Synthesis is divided into two processes: Transcription and Translation Transcription
A section of DNA is copied into mRNA; this takes place in the nucleus
Remember: RNA has U instead of T Translation
mRNA codons are translated into amino acids with the help of tRNA.
A ribosome attaches the amino acids to form the protein
This takes place in the cytoplasm
Transcription and Translation
TEK 6DRecognize that gene expression is a regulated process express = “turn on” Repress = “turn off”
Environmental Factors The expression of genes in an
organism can be influenced by the environment
Factors include: Gender Chemicals Temperature light
Gene Regulation Gene regulation in eukaryotes takes
place during each phase of the process Chromatin Remodeling-the region of the
chromosome must be open in order for the gene to be accessed
Transcriptional Control-most common type; can turn on or off mRNA
Translational Control-regulation of the rate; make an inactive protein active
TEK 6GRecognize the significance of meiosis to sexual reproduction
Chromosome Structure Chromosome: a single piece of
coiled DNA containing many genes
Homologous Chromosome: each chromosome has a match. This is why you have 46(even number). You get 23 from each parent
Sex Chromosome: X and Y; determine the sex of the organism; XX= female, XY = male
Process of MeiosisMeiosis: the production of haploid cells with unpaired chromosomes
Broken down into two phases: Meiosis I Meiosis II
Key points of meiosis The process results in 4 daughter cells Daughter cells are haploid(23
chromosomes) Daughter cells have unique
combinations of chromosomes Daughter cells do not have homologous
pairs Meiosis creates gametes(sperm and
eggs) Meiosis ensures variability in offspring
Independent Assortment and Crossing over Independent assortment: alleles for a
particular phenotype determine what characteristic an organism will express When alleles separate during metaphase I it
is random which cell each allele ends up in Crossing over:The exchange of genes
between homologous chromosomes, resulting in a mixture of parental characteristics in offspring. This increases genetic variability
Mitosis vs. Meiosis
TEK 6HDescribe how techniques such as DNA fingerprinting, genetic modifications, and chromosomal analysis are used to study the genomes of organisms
Human Genome Project Completed in 2003 13 year project Goals:
Identify all the 20,000-25,000 genes in human DNA
Use data to improve medical technologies and treatments
Address ethical, legal and social issues
Manipulating DNA Genetic Engineering is the process of
reading and changing DNA sequences in an organism
1. DNA extraction 2. Cutting and Labeling DNA 3. Separating DNA 4. Reading the DNA sequence 5. Making copies(PCR)
Uses of Gel Electrophoresis DNA Fingerprinting
Paternity tests, crime scene samples Gel electrophoresis is used to separate the
DNA sample into pieces The position and length of bands are
unique like a fingerprint Material you can get samples from:
Blood Hair Saliva Semen Body tissue cells
Gel Electrophoresis