Unit 6: Chapters 23, 24, & 25: Genetics

Understanding our genes and the ways they are passed to the next generation.

Basic Genetics Modern Genetics

A. Basic Genetics

_________________ = study of heredity

understanding of how ______________ get ________ from ___________________, _____________________

1. Traits = characteristics hair color, eye color, widows peak, tongue rolling, ear lobes

2. Gene Chromosome Theory - ________________________________________ found in the nucleus - Because of ______________________ (2 of each chromosome) ______________________________ __________________________ called _____________________

- Remember that through meiosis each parent only passes

on __________________________

- Through fertilization the ____________________ of genes

is restored

- Organisms can have

____________________

the __________________

_________________ of the

organism

3. _______________________________________________ When ___________________________________ there is a ____________________________________ on homologous chromosomes.

______________________________________________. As a consequence, _________________________ are likely

to be produced.

4. _____________________________________________ _________________________________________________ __________________ (nonhomologous chromosomes), they _______________________________ and, therefore, may be ______________________________ of each other. (not linked)

5. ________________________________ __________________________________________. The __________________________________________________.

6. Probability and Inheritancea) _____________ = genetic make up / ___________ of an individual

______________ = same alleles (TT or tt)______________ = different alleles (Tt) = Hybrid

b) ____________ = ___________________ (Tall or Short)Usually _______________________ – sometimes the______________ can affect the phenotype.

Can two organisms have the samephenotype but different genotypes?

c) Punnett Square representation of _____________________ and the different _____________________________________

ex: Cross: Homozygous Tall x Homozygous Short

1. Determine the genotypes of the parents

2. Determines the possible gametes of the parents

3. Write the gametes on the outside of the box

4. Combine the parents gametes

Remember only 1 gamete from each parents

All the offspring are genotype Tt – heterozygousThe genotype tells the phenotype – Tt TallIn the heterozygous the recessive allele is hidden

ex: Cross: Heterozygous Tall x Heterozygous Tall

What is the genotype ratio?

What is the phenotype ratio?

Through his knowledge of math and detailed record keeping, with 10,000s of pea plants Gregor Mendel always had this ratio in the phenotypes.

a) ________________- a diagram of family relationships that uses symbols to represent people and lines to represent genetic relationships. - easier to visualize relationships within families- Pedigrees are often used to determine the mode of inheritance (dominant, recessive, etc.) of genetic diseases.

B. Human Inheritance

b) Human Genetic Diseases / Disorders1) _______________

recessive allelelack pigment in skin, hair, eyes

2) ________________recessive alleleexcess mucus in lungs;

increases susceptibility to infections; death in childhood unless treated

3) ___________________ recessive alleleaccumulation of phenylalanine

(amino acid) in tissuebody can not break down the

amino acidmental retardation if they eat

phenylalanine

4) _________________recessive allelehigher occurrence (1/100 vs 1/100,000) in Jewish families of eastern European ancestrylipid accumulation in brain cells, nervous system break down death in early childhood

5) ______________________ dominant allelebones fuse and stop growth

6) ______________________ codominant allelered blood cells have a crescent shape misshapen hemoglobincan not carry O2 as well

7) ____________________dominant alleleextra toes and fingersnot always expressed

8) ______________________chromosomal disorderextra 21st chromosome cause by nondisjunction

1. _____________________ – 1950’s Used Rosalind Franklin’s x-ray pattern of DNA to build its 3-D structure Double helix with complimentary base pairs

a) DNA Structure __________________ A = ________________ B = ________________ C = ________________

A – TG – C

__________ _______ _____________From the human to the DNA – PBS Flash

C. Modern Genetics

DNA STRUCTURE

MOVIE

2. DNA Replication a) Occurs inside the __________________ b) DNA molecules ____________________, then produces _______________________________________________ _________________ c) Each original strand serves as a template for the new strand

T A C C G G A C C C G T A G G C A A T A GA T G G C C T G G G C A T C C G T T A T C

Original DNA DNA “Unzips”

T A C C G G A C C C G T A G G C A A T A G

A T G G C C T G G G C A T C C G T T A T C

Enzymes fill in nucleotides

Check out this site on your own for a more detailed explantation

More Complicated but explains the process really well.

http://207.207.4.198/pub/flash/24/menu.swf

Easy Version of DNA Replication

3. Protein Synthesis

a) RNA = ___________________

_________________ nucleic acid

contains Ribose as the sugar not __________ as in DNA

has the base ________ instead of _________ as in DNA

Types of RNA ______ = ______________ carries gene out of the nucleus rRNA = ribosomal RNA makes up ribosome ______ = ______________ brings in amino acid

b) Transcription

1st step of protein synthesis; similar to replication

_________________________

Occurs in the ______________

“Unzip” DNA – uses 1 side of DNA as a template

RNA polymerase fills in complimentary RNA bases

mRNA detaches from DNA

mRNA leaves nucleus

Simple Trasncription Animation

Just another Trancription animation

T A C C G G A C C C G T A G G C A A T A G

A T G G C C T G G G C A T C C G T T A T C

Original DNADNA “Unzips”

A U G G C C U G G G C A U C C G U U A U C

Enzymes fill in RNA nucleotidesRNA breaks from DNADNA reconnects

The groups of 3 bases on the mRNA is called a CODON

The codon codes for specific amino acids when making a protein

c) Translation2nd step of protein synthesis__________________________________________occurs in the ______________ at the ____________________________________________________Matches the _______________________________

________ reads next _____ and brings in next tRNA with matching anticodonSince _____ is attached to ________ – two amino acids are located next to each otherThis proximity allows the ________________Makes a _____________Repeats until mRNA says stop

More than 1 ribosome can attach to the mRNA at a time

Makes multiple peptides

Translation Animation

d) Protein Synthesis Overview

e) Genes code for peptides generally a protein is the combination of more than 1 peptide

To see it in some more detail check out the following website on protein synthesis

http://learn.genetics.utah.edu/content/begin/dna/

Try this website as an interactive for replication and protein synthesis

http://www.pbs.org/wgbh/aso/tryit/dna/shockwave.html

4. Mutations

Changes in the DNA sequence

Some are good

Some are bad

Most are neutral

Mutations are only passed to the next generation if they occur in gametes

Mutations in somatic cells are not passed – acquired characteristics are not passed

a) Gene Mutationschanges in a single gene

1) Point Mutations – involve just one nucleotidesubstitution = change one nucleotide for anotherex:

T A C G C G A C C C G A becomesT A C G C C A C C C G A the change may or may not change the amino acid

2) Frameshift Mutationsinsertion or deletion of a single nucleotidechanges the codons read by the ribosomeusually affects all amino acids after the mutationex: DNA: T A C C G G A C C C G A

mRNA: A U G G C C U G G G C UAmino A: Met Ala Try Cys

InsertionDNA: T A C G C G G A C C C G

A mRNA: A U G C G C C U G G G C

UAmino A: Met Arg Leu Gly

The order of amino acids changed changes protein (big time)

Ex:

delete 1 letter

THE FAT CAT ATE THE RAT THE FTC ATA TET HER AT ????

Completely change everything after the deletion

No longer makes sense The same thing happens with the protein

The order of the letter (amino acids) determines the structure of the words and sentence (protein)

One little mistake can completely change the meaning

b) Chromosomal Mutations

changes the structure of a chromosome

rearrange the genes on a chromosome

1) _______________________

2) _______________________

3) _______________________

4) _______________________

Chromosomal Mutations

c) Mutagenic Agents factors that cause mutations 1) ___________________ –

X-rays _________________ radioactive substances, and cosmic rays

2) ______________ – formaldehyde, benzene, asbestos fibers _______________

_______________

D. DNA Technology ways in which the knowledge of DNA can help benefit society

a) _________________________ __________________ in organisms, mating the organisms, and hoping some of the offspring have the combinations of the traits

ex: dogs, cattle, crops selective breedinghas been occurring for 1000s of years

b) ______________________________ __________________; transfer DNA from one organism to anotherisolate gene ____________________________ _____________________________ place recombinant DNA in a new organism*restriction enzymes = cut DNA at very specific sequences

can be used to make a variety of products

c) ________________

making an _______________

Remove the nucleus of an egg cellUse the nucleus of a body cell Insert the nucleus into the egg cell Grow the egg cell Identical genetic copy of the body cell

organism

Click and Clone

d) ________________________making “__________________”

use restriction enzyme to cut DNA into fragments

place DNA into a porous gel electrify gel and DNA fragments

move small pieces move the farthest

Gel Electrophoresis - Learning Center

Gel Electrophoresis Virtual Lab

e) Human Genome Project sequence all human DNAmap and locate all thehuman genes about3,000,000,000 base pairs inorder

help to find and cure diseases

Gene Therapy find defective gene andreplace it with a healthy gene