Transcript Chapter 10 Lesson 1

Chapter 10
Lesson 1
Polypeptide Synthesis
Read pg. 248 and pg.250 (1st
paragraph)
I. Transcription
A. Def – making RNA from DNA
B. RNA (ribonucleic acid)
1. Characteristics vs. DNA
a. single chain / not double helix
b. ribose
c. contains uracil (U) instead of
thymine
2. *Formation of RNA (pg. 251)
a. cell activates
b. enzyme attaches and unzips DNA
c. RNA copies DNA – forms single chain
d. RNA breaks away; DNA rejoins
*remember U takes the place of T
3. Types of RNA
a. mRNA – codes for polypeptides/proteins
b. rRNA – makes up ribosomes
4. Complete the RNA code…
DNA CODE
…AGC TTA TCC AGG…
RNA CODE
…UCG AAU AGG UCC
DNA CODE
…GCA AAT CGA TAG GAA TAC CCA…
RNA CODE
…CGU UUA GCU AUC CUU AUG GGU…
5. Transcription in Eukaryotes...pg. 252-253
a. Introns – do not code for a.acids
b. Exons – code for a.acids
(expressed)
c. Why introns…?
1. no current function
2. ancient genes that have lost
function
3. remnants of viruses
d. Process called mRNA processing
pg. 253
II. Translation
A. Def – synthesis of a protein from the
info of a mRNA.
B. tRNA – carrier of amino acids to the
ribosome. – pg. 254
1. cloverleaf structure
2. ATP used to connect a.acids
3. anticodon – 3 bases (opposite) of
what the tRNA has to carry.
C. Joining of codons and anticodons
1. ribosome attaches to mRNA
2. tRNA approaches w/ a.acid
3. a.acid chain begins to grow
4. 2nd tRNA approaches w/ a.acid
5. a.acid chain begins to grow
6. old tRNA breaks off
7. stop signal – protein or polypeptide
forms
Chapter 10
Lesson 2
“Sources of Variation”
Introduction pg. 261 – 1st
paragraph
I. Mutation
A. Def – the genetic info from
a parent cell is different than
that of a daughter cell
1. Deletion (pg. 262)
a. Nucleotide(s) is left out
2. Insertion
a. Extra nucleotide(s) is put in
b. Ex: Normal Code AUG AGU CAA
Tyrosine
Serine
Valine
After Mutation AUG GAG UCA A
Tyrosine Leucine Serine
c. Examine the amino acids
3. Point Mutation
a. One nucleotide is substituted for
another. This only changes one
a.acid
B. Mutagen
1. Def – External agents that cause
mutations
a. Ex: radiation, high temp,
chemicals, environmental factors
C. Mutations
1. Body cells – only cause problems in person
2. Sex cells – problems are passed from
generation to generation
D. Chromosome mutations
1. Chromosomes parts rejoin in a new
order.
II. Other genetic variations
A. Gene Duplication
B. Cancer
1. Mutations
a. Carcinogens
b. Oncogenes – cancer causing genes
2. Viruses – HPV shots, HIV