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BIG PICTURE:
MAKING PROTEINS
• DNA 
RNA
 PROTEIN
• Nucleus Cytoplasm Ribosomes
WHY PROTEINS??
• Proteins are polymers = CHON
– Proteins make up ENZYMES, muscles, hair, nails, and code for
traits
• Amino acids held together by
peptide bonds
– There are 20 amino acids in nature
• Function of the protein depend on the twists and
folds
8.4: Transfer of Genetic Information
• DNA  RNA
• RNA:
–
–
–
–
–
Is Ribonucleic acid (isn’t missing the oxygen)
Has RIBOSE as the sugar
Can leave the nucleus to go to ribosomes
Is single stranded
No “T”s…has Uracil (U) bonding to A
Transcription
• The process by which the genetic information
in DNA is copied to RNA
– The code is TRANSCRIBED…DNA to RNA
– In NUCLEUS
f
8.5: Translation
• The process of assembling proteins
– RNA  PROTEIN
– Have to code for tRNA too which has an
anticodon so the AA can be
TRANSFERRED to ribosomes
TOPIC: GENE EXPRESSION and
GENETIC ENGINEERING
• OBJECTIVE: LOOK AT
BIOTECHNOLOGY (Ch 8.7-9.6)
GENE EXPRESSION
• Promoter
– DNA segment that promotes
transcription and recognizes mRNA
(where transcription begins)
• Structural Genes
– Genes that code for particular proteins
Controlling Gene Expression
• Conserve resources
• Only make proteins when needed***
Structure of Eukaryotic Gene
• Promotor
– Where transcription begins
• Beyond the promotor
– Introns
• Sections of genes that do not code for amino
acids; no proteins are made
– Exons
• Sections of genes that do code for amino
acids, so proteins are made
• Less than 10% of a human gene
……
Mutations
• Any mistake or change in the
DNA sequence
– Accuracy of DNA is important to
ensure genetic continuity of new
cells and offspring
3 types of mutations:
• 1. Point mutations: change in ONE DNA base
– This would change the meaning of the codon on the
mRNA
– Example:
• THE DOG BIT THE CAT
• THE DOG BIT THE CAR = mutation
mutate
d
base
3 types of mutations:
• 2. Frameshift mutations: a single base is added or deleted
from DNA
– This would cause every codon to be wrong from that
point on in protein coding
– Example:
• THE CAT ATE THE FAT RAT
• THE ATA TET HEF ATR ATT
3 types of mutations:
• 3. Chromosomal mutations:
– Affects the entire chromosome
– If a chromosome is missing= monosomy
• Monosomy on Sex Chromsomes = Turner
Syndrome
– 45 chromosomes in humans
– May involve an extra chromosome = trisomy
• Trisomy on Chromosome 21 is Down Syndrome
– 47 chromosomes in humans
CAUSES OF MUTATIONS
• Mutations can be good, bad or nothing
– They are usually random events but….
• Errors in DNA provide the variation that must be
present for the evolution of species