Transcription and Translation Notes

Question 1

How is DNA different from RNA?

Answer 1

-RNA is a single strand
- An RNA Nucleotide has three parts:
Phosphate Group
Bases (Cytosine,
Guanine, Adenine or
URACIL)
Ribose Sugar

Question 2

mRNA –

Answer 2

-Messenger RNA
Transmits information from DNA for use during protein
synthesis, serves as a template
Form is a characteristically long, single strand

Question 3

Most common forms of RNA

Answer 3

mRNA, tRNA, rRNA

Question 4

tRNA

Answer 4

Transfer RNA
Carries amino acids to ribosomes during protein synthesis
Form is a single stranded molecule folded back on itself

Question 5

rRNA

Answer 5

Ribosomal RNA
Makes up the ribosomes
Form is characteristically globular

Question 6

snRNA

Answer 6

Form of RNA found in the nucleus, important in splicing of RNA and maintaining telomeres

Question 7

RNAi

Answer 7

(RNA Interfaces)– forms of RNA used in gene silencing, can turn genes on and off

Question 8

Transcription

Answer 8

The process by which mRNA is copied
from DNA
- RNA polymerase: the enzyme that catalyzes the reaction of transcription
- Transcription continues until one entire gene has been copied into mRNA

Question 9

Steps in Transcription

Answer 9

RNA polymerase initiates process by binding to
specific regions called promoters found at start
of gene sequences
2. Base pairing rules from replication are same, but
U A and the entire coding region is copied
3. Transcription continues until RNA polymerase
reads a terminal signal in the DNA sequence,
the RNA molecules detach and move to
cytoplasm for protein synthesis

Question 10

Exons

Answer 10

Are regions of expressed DNA

Question 11

Introns

Answer 11

Are regions of non-expressed DNA

Formally known as “junk” but now known to control protein synthesis

Question 12

The Central Dogma:

Answer 12

DNA is transcribed to RNA which is translated to PROTEIN

Question 13

Exeptions to Central Dogma

Answer 13

Retroviruses and Prions

Question 14

Retroviruses

Answer 14

Are an exception to the Central Dogma where RNA makes DNA which then makes RNA and Proteins HIV is one of the most commonly known retroviruses

Question 15

Prions

Answer 15

Diseases that appear to be spread through proteins only, without the process of the central dogma.
 Examples
- Inherited: CJD,
- Infectious: Mad Cow
Disease, Kuru

Question 16

Code chart thing

Answer 16

This codon chart shows
the amino acid-codon
combinations for all living
things.
-There are 64 possible codons, but only 20 different amino acids…why?
-The genetic code is universal – UUU codes of
Phenylalanine in virtually all organisms on earth.

Question 17

The Transcript is the Template

Answer 17

mRNA (the transcript or code) consists of a long chains of
nucleotides copied from the DNA template strand
A specific group of three nucleotides on the mRNA is a codon
A codon specifies for a specific amino acids in the protein
The codon will match with an anticodon on the tRNA (which
transports in the amino acids)

Question 18

Start Codons

Answer 18

-Tells the ribosome to
begin protein
synthesis.
-Also codes for the
amino acid methionine.
-There is only one start
codon: AUG

Question 19

Stop Codons

Answer 19

• They tell the ribosome to stop protein synthesis.
• Does not code for any amino acids
• There are 3 of them:
  1. UGA
  2. UAA
  3. UAG

Question 20

Steps of Translation

Answer 20

Ribosome attaches to start codon on a mRNA molecule
2. The start codon will pair with the anticodon UAC on a
tRNA
3. The tRNA also carries the amino acid methionine.
4. As the ribosome moves along an mRNA transcript,
each mRNA codon is sequentially paired with its tRNA
anticodon
5. Amino acids are joined to a growing polypeptide chain
in the order specified by an mRNA transcript
6. When the ribosome reaches a stop codon, translation
ends

Question 21

Gene Mutations

Answer 21

Changes to a single nucleotide , point mutations, make
changes inside a single gene
Frameshift Mutations: Type of point mutation that leads to
the misreading of the rest of the mRNA molecule

Question 22

Chromosomal Mutations

Answer 22

A change in the entire chromosomes, changing an
entire gene!
A. Deletion:
B. Duplication:
C. Inversion:
D. Translocation:

Question 23

Epigenetics Regulation

Answer 23

The same set of genes but with expressions (structures) of those genes during different life stages