Genetics Powerpoint Regents Biology

Genetics : Genetics Green Review book: Chapter 7 pgs 97-115 Black review book: Chs. 19-23 pgs 143-178 Hard textbook: Chs 11-14 pgs 262-365

Slide 2 : "If our strands of DNA from one cell were stretched out in a line, the 46 chromosomes making up the human genome would extend more than six feet If the length of the 100 trillion cells could be stretched out, it would be ... over 113 billion miles. That is enough material to reach to the sun and back 610 times."

Slide 3 : Gene Chromosome Theory

Slide 4 : Gene – specific, short sequence of DNA that codes for a trait (protein)

Why do we call the nucleus the control center?? : Why do we call the nucleus the control center?? DNA holds instructions to make PROTEINS All enzymes are PROTEINS Enzymes control ALL chemical reactions in a cell

Heredity : Heredity Transfer of genes from parents to offspring Chromosomes with genes are carried by sperm and egg

Slide 7 : DNA Structure & Replication

Slide 8 : Long polymer chain Watson and Crick - Revealed the structure of DNA to be a double helix Analogy – spiral staircase Handrails – repeating sugar-phosphate backbone Steps/rungs – nitrogenous bases

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Slide 15 : phosphate Deoxy-ribose sugar Nitrogenous base

Slide 16 : nucleotide

Slide 17 : Sugar-phosphate backbone - Repeating pattern of sugar-phosphate-sugar-phosphate…. Nitrogenous bases - arranged as appendages along this backbone attached to each sugar

Nitrogenous Bases : Nitrogenous Bases A = Adenine T = Thymine (only in DNA!!) C = Cytosine G = Guanine U = Uracil (only in RNA!)

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Slide 22 : DNA: A pairs with T G pairs with C DNA RNA: A pairs with U G pairs with C Complementary Base Pairing

Slide 23 : What would be the complementary base sequence for the following DNA strand? A A T T G G C A T G C A

Slide 24 : T T T T G C A G A T G A C G A T

Hydrogen bonds!! : Hydrogen bonds!! Hold together the two complementary DNA strands

DNA Replication : DNA Replication DNA – only molecule that can make exact copies of itself Occurs during S-phase of interphase

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DNA replication is semi-conservative : DNA replication is semi-conservative new DNA has 1 old strand w/ its complementary new strand

Step 1 : Step 1 Enzyme breaks H bonds Strands separate Replication fork formed

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Step 2 – : Step 2 – DNA Polymerase (Enzyme) adds nucleotides to naked DNA strands Follows base-pairing rules Also “proof-reads” new strands

Step 3 - : Step 3 - DNA polymerase falls off when done 2 identical DNA strands

Prokaryotic Replication : Prokaryotic Replication circular DNA ONE replication fork only!!!

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RNA & Protein Synthesis –Transcription & Translation : RNA & Protein Synthesis –Transcription & Translation

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Slide 39 : Genetic information must pass from nucleus to ribosome in cytoplasm!!

Slide 40 : DNA ? RNA ? protein (trait)

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RNA DNA : RNA DNA Single stranded Shorter No Thymine!! Uracil (U) pairs with Adenine Ribose sugar Double stranded Longer Thymine Deoxyribose sugar

RNA : RNA mRNA Messenger RNA carries DNA info. (gene) from nucleus to ribosomes in cytoplasm

Slide 44 : rRNA (ribosomal RNA ) rRNA + protein = ribosome

Slide 45 : tRNA Transfer RNA Transfers amino acids from cytoplasm to the growing polypeptide chain on the ribosome

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Two main stages of protein synthesis: : Two main stages of protein synthesis: 1 - Transcription transfer of genetic information from DNA?mRNA Occurs in the nucleus Process can be imperfect leading to altered messages and therefore altered proteins

Slide 50 : 2 - Translation Occurs in cytoplasm transfer of information in the mRNA?protein

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The Genetic Code : The Genetic Code Rules for how a codon translates into an amino acid sequence (protein)

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Translate the following mRNA sequences into the corresponding amino acid sequence : Translate the following mRNA sequences into the corresponding amino acid sequence CCA UUU ACG CCG UGC AUA CAG GUA

Translate the following DNA sequences into the corresponding mRNA seqeunce, and amino acid sequence : Translate the following DNA sequences into the corresponding mRNA seqeunce, and amino acid sequence 3. CCG TGC ATA CAG GTT 4. CCT TGT ATG CAC GTC

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Gene Expression : Gene Expression ALL cells in an organisms have ALL of the organism’s genes Differentiation= cells turn certain genes “off” and leave certain genes “on.” Ex -

Heredity & Environment : Heredity & Environment Ex - “Nature vs. Nurture” Genes can be turned “on” under the influence of environmental conditions

Slide 63 : Ex – Plants inherit gene to make chlorophyll, but gene is not turned “on” until the plant receives light Identical twins have the same genetic information, but can appear different Ex -

Recessive vs. dominant alleles : Recessive vs. dominant alleles Allele – variation of a gene Ex – gene for hair color has many alleles: brown, blonde, black, etc… Genotype – Phenotype -

Slide 65 : Epigenome: http://www.youtube.com/watch?v=AV8FM_d1Leo&feature=related

MUTATIONS : MUTATIONS

Mutations : Mutations Any change in the nucleotide sequence of DNA Mutations can occur on an entire chromosome OR in one particular gene

Slide 68 : Germ-cell mutation Somatic–cell mutation Lethal mutation Beneficial mutation

Chromosomal Mutations : Chromosomal Mutations

DELETION : DELETION Portion of a chromosome is missing

INVERSION : INVERSION Segment of the chromosome becomes flipped/inverted

Slide 72 : http://www.maxanim.com/genetics/Inversion/Inversion.htm

TRANSLOCATION : TRANSLOCATION Piece of one chromosome breaks off and accidentally attaches to another non-homologous chromosome

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Aneuploidy : Aneuploidy One or more pairs of homologues fail to separate during anaphase Ex -

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Detection of chromosomal mutations : Detection of chromosomal mutations

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Gene Mutations : Gene Mutations

Slide 83 : Damaged or changed genes Change to the base sequence Cause a different mRNA to be transcribed and translated Result??

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Translate the following sequence: : Translate the following sequence:

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Translate the sequence when a Uracil is deleted by mutation : Translate the sequence when a Uracil is deleted by mutation

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Slide 91 : One wrong letter: http://www.pbs.org/wgbh/nova/genome/dna.html#

How do mutations arise? : How do mutations arise? Spontaneous mutations – due to errors in DNA replication, repair, or recombination mutagens

Mutagens : Mutagens chemicals that interact with DNA and cause mutations

Slide 94 : Ultraviolet light Radiation X-rays Chemicals Certain viruses Air or water pollution Electromagnetic waves Cosmic rays

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Genetic Engineering : Genetic Engineering

Genetic Engineering : Genetic Engineering New technology humans use to alter genetic instructions

Selective Breeding : Selective Breeding HUMANS CHOOSE which traits are best and cross them to pass desired traits on to the next generation of organisms Ex – choosing the “beefiest” cows to mate, crossing the plants that bear the largest fruits

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Hybridization : Hybridization Crossing the most desirable traits of two organisms to create an “ideal” organism Problem: effects on humans are unknown

Artificial Selection vs. Natural selection : Artificial Selection vs. Natural selection Nature provides the variation Humans choose which traits suit their needs and breed accordingly Selective breeding Ex - Nature “chooses” Organisms with variations most suited to the natural environment survive and leave more offspring

Cloning : Cloning Genetically identical offspring produced from one cell

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Restriction Enzymes : Restriction Enzymes Enzymes cut at SPECIFIC sequences ONLY! Can cut human DNA & prokaryotic DNA Can also be used to make a recombinant piece of DNA

Transformation : Transformation Produces a recombinant DNA Scientists identify the gene of interest Ex – humans genes can be inserted into plant and bacterial genomes The bacteria and plants produce human proteins & enzymes

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Slide 113 : 1 - use enzymes to cut a desirable gene out of human DNA 2 - use enzymes to cut a desirable gene out of bacterial DNA 3 -use enzymes to put the two together 4 - Asexual reproduction -makes more copies of gene -makes more desired HUMAN protein

Slide 114 : Gel Electrophoresis

Gel Electrophoresis : Separates fragments of DNA based on size Gel Electrophoresis

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Step1: DNA cut into fragments by restriction enzymes : Step1: DNA cut into fragments by restriction enzymes

Step 2: Cut up DNA is loaded into a gel : Step 2: Cut up DNA is loaded into a gel

Step 3: Electricity applied to chamber : Step 3: Electricity applied to chamber

Step 4: DNA fragments separated because of size & charge : Step 4: DNA fragments separated because of size & charge

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Pedigree Analysis : Pedigree Analysis

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