Nucleotides: Subunits of DNA
• A nucleotide consists of a ______, a ______, and a _____. Nucleotides are identical except for their base.
• There are 4 bases: A_____, T_____, G_____, and C______
• All four bases have a different _____.
Chargaff’s Rules
• Guanine and Cytosine always occur in _____ _______ in DNA, as do Adenine and Thymine
Franklin’s Discovery
• Used X Ray diffraction to make images of DNA molecules
• Suggested the ____ shape of DNA
Watson and Crick’s Model
• After seeing Franklin’s image, Watson and Crick concluded that DNA must look like a ____, ______ ______.
• This helped explain how DNA is ______ and how it ______ in the cell.
DNA’s Double Structure
• Double Helix, two sides of the ladder are made of alternating _____ parts and ________ parts.
• The rungs of the ladder are made of a pair of bases:
A______-T______G______-C______
Animated DNA
• http://highered.mcgraw-hill.com/sites/0072943696/student_view0/chapter3/animation__dna_replication__quiz_1_.html
Making Copies of DNA
• Pairing the bases allows the cell to _______ or make copies of DNA
• The pairs are _____________ since they always pair A-T and G-C
How are copies made?
• During replication, a DNA molecule is _____ ____ the _______, where _____ meet.
• The bases on each side of the molecule are used as a _________ for the new strand.
• As the bases on the original molecule are exposed, _________ ________ are added to each side of the ladder.
• Two DNA molecules are formed.• Half of each of the molecules is
old DNA, half is the new DNA
Unraveling DNA
• DNA is often wound around ______, coiled into strands, and bundled up even more.
• Cell’s without a nucleus the DNA forms ______ ______ within the cell.
• Cell’s with a nucleus the DNA and proteins are bundled into __________.
When are copies made?
• DNA is copied …• The job of ________, ________ and
__________ the DNA is done by proteins within the cell.
Unraveling DNA
• The structure of DNA allows it to hold ________.
• The ______ of the bases is the code that carries the information.
• A gene consists of
• Humans have over ______ genes.
• 2003 Human Genome Project
Unraveling DNA- Quiz
• Where is the DNA in your cells?
• How does so much DNA fit into the nucleus?
• What is the name for strands of DNA wound around proteins?
• When do chromosomes become visible in cells?
• What are chromatids?
• In • It is • C• When the • Two
Genes and Proteins
• DNA code is read like a book, from one end to the other and in one direction.
• Bases form the alphabet of the code.
• Groups of __ bases are code for the ____ _____ profile. (example: AGC)
• A long string of amino acids forms a ______.
• Each gene is
Proteins and Traits
• Proteins are found _______ cells and cause most of the _______ that you see among organisms.
• Proteins act as _______ ________ and ________ for many processes within the cell.
• A single organism may have _______ of genes that code for thousands of proteins.
Making of a Protein
• Step 1: A copy is made of one side of the DNA segment where a particular gene is located. This copy is transferred to the _________.
Making of a Protein
• Step 2: This mirror like copy of a DNA segment is called messenger RNA (mRNA).
Messenger RNA..
Making of a Protein
• Step 3: Each group of ____ bases on the mRNA segment codes for ___ amino acid.
Making of a Protein
• Step 4: The mRNA segment is fed through the _______. A ribosome is a cell organelle composed of ____ and _______.
Making of a Protein
• Step 5: Molecules oftransfer RNA (tRNA) deliver amino acids from the cytoplasm to the ribosome.
Transfer RNA (tRNA) transfers
Making of a Protein
• Step 7: The amino acids are joined to make a ______. Usually, one protein is produced for each _____.
Animated mRNA
• http://highered.mcgraw-hill.com/sites/0072943696/student_view0/chapter3/animation__mrna_synthesis__transcription___quiz_1_.html
How is RNA different from DNA?
• RNA: one strandcontains ______ instead of thymine A, G, C, U
• DNA: two strands A, G, C, T
Changes in Genes• Mutation: a change in the nucleotide-
base sequence of a gene or DNA molecule
• Either __________, ________ or ___________
• Causes an ___________, __________ or _____________
• If the mutation occurs on the sex cells, the mutation can be passed to the _______ _________
• Mutations happen _______ • Mutagens are any physical or chemical
agent that can cause the mutation (examples: UV radiation, X rays, cigarette smoke)
• Examples are
Example of Substitution
• Sickle Cell Anemia- affects red blood cells. When _______ is substituted for _______ _______ in a blood protein. The change in shape isn’t good for the cell to carry oxygen and clot in vessel (very painful).
Genetics
• Genetic Engineering: Manipulate individual genes to create new products, such as foods, drug or fabrics
• Genetic Identification: DNA is your unique fingerprint, only identical twins share DNA
Clone:
Selective breeding: A technique to produce offspring with desirable traits. Inbreeding:
Hybridization:
Web sites…..• DNA and Genetics:• http://www.pbs.org/wnet/dna/episode1/index.html#• http://www.pbs.org/wgbh/aso/tryit/dna/• http://learn.genetics.utah.edu/content/begin/dna/• http://www.biology.arizona.edu/human_bio/activities/karyotyping/karyotyping.html• http://www.mesacc.edu/~tinhw34501/psquare.pdf• http://www.nature.ca/genome/05/051/0511/0511_m205_e.cfm• http://www.pbs.org/wgbh/nova/body/sequence-DNA-for-yourself.html• http://www.pbs.org/wgbh/aso/tryit/dna/shockwave.html • Genetics:• http://pbskids.org/dragonflytv/games/game_dogbreeding.html• http://www.worldwildlife.org/sites/inner-animal/index.html• http://anthro.palomar.edu/mendel/mendel_2.htm• http://www.athro.com/evo/gen/punexam.html• http://www2.edc.org/weblabs/Punnett/punnettsquares.html• http://biology.clc.uc.edu/courses/bio105/geneprob.htm• http://www.cellsproject.org/examples/sc/page23.html• http://glencoe.mcgraw-hill.com/sites/0078778066/student_view0/chapter5/math_practice.html• http://anthro.palomar.edu/mendel/mendel_1.htm• http://www.biology.arizona.edu/Mendelian_genetics/mendelian_genetics.html• http://www.ndsu.edu/pubweb/~mcclean/plsc431/mendel/mendel1.htm• http://www.pbs.org/wgbh/nova/body/cracking-the-code-of-life.html