BASICS DNA is hereditary information It is located in the nucleus of a cell DNA is a long polymer made up of many monomers The building blocks are called nucleotides ○ There are four nucleotides A = T C = G
Two Jobs 1. Pass on information to offspring Divide the material in half and put into gametes Allows for a full set of chromosomes after fertilization 2. Tell the body what to do by building proteins!
DNA Replication DNA “unzips” Nucleotides fill in missing strands resulting in two identical DNA strands
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Interpret and respond. Draw or write:
DNA as Instructions DNA is a code for building proteins Proteins construct our body Our blood cells, skin cells, hormones, enzymes, toe nails etc. When our body needs to make a new protein or part it needs to “read” its DNA
Review - Proteins Proteins are a polymer chain The monomer of proteins are amino acids Proteins are made of amino acids There are 20 amino acids The structure or shape of a protein determines its job
Many, many shapes of proteins
Making proteins from DNA Ribosomes located in the cytoplasm of a cell build proteins coded for in our DNA DNA is too large to leave the nucleus though ○ So how do we do it?
Step one - Scribe What did a scribe do? What do you think it means to transcribe?
1. Transcription The gene that is needed will unwind The portion to be made will be duplicated into a single complementary RNA strand STEP 1 ○ DNA STRAND = A T C G T T ○ RNA STRAND =_______________ RNA does not have T’s! Instead they use U’s. STEP 2 ○ Change all T’s in your sequence to U’s!
This RNA strand can leave the nucleus It will attach to a ribosome
Translate – what does it mean?
2. Translation Once attached to the ribosome the ribosome will start to interpret or translate the RNA strand into amino acids Remember a string of amino acids makes a protein! Every three nucleotides codes for one amino acid This is called a codon
Translation animation Genetics/17%20Translation.GIF
Step 3 – count off and mark every 3 nucleotides in the RNA strand Three nucleotides to a reading frame! Step 4 – use the codon wheel to identify the amino acids that are coded for!
A change in the genetic code
1. The sky is blue and the sun shines. 2. The sky is red and the sun shines. 3. The sky is green black sun hot rays fell 4. The sky is blue and green sky sky
Point Mutation Single nucleotide is substituted Affects one amino acid
Frameshift mutation Deletion or insertion of a nucleotide Changes the reading frame for following sequence
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Not all mutations are bad! Mutations account for variation in a species Its how certain physical characteristics started developing in organisms If a mutation arises and it helps an organism compete, that mutation will be passed down to more offspring
Some mutations are bad! There are two types of mutations Point mutation ○ Substitution Frame Shift mutation ○ Deletion ○ Insertion
Genetics Disorders Caused by a single point mutation Sickled blood cells clog capillaries reducing and sometime cutting off blood flow and oxygen supply Caused by one of 900 identified mutations to genes for mucus production in the lungs Cells produce too much mucus clogging the lungs
Genes that instruct cell growth and division (MITOSIS) are mutated The cell doesn’t know when to stop dividing Cells become invasive damaging surrounding tissues and disrupting homeostasis
Kleinfelter Syndrome XXY
Turner Syndrome XX