Protein Synthesis

Question 1

Protein Synthesis

Answer 1

process of reading the instructions in DNA to make a polypeptide

Question 2

Polypeptide

Answer 2

chain of amino acids- can bind to others and fold into a protein

Question 3

Central Dogma of Genetics

Answer 3

-DNA’s instructions are in the nucleus, but DNA cannot leave the nucleus
-proteins are made in the ribosomes
-Protein synthesis takes 2 steps: Transcription and Translation

Question 4

3 Types of RNA

Answer 4

-mRNA (messenger)
-tRNA (transfer)
-rRNA (ribosomal)

Question 5

mRNA

Answer 5

copies instructions in DNA and carries these to the ribosomes in the cytoplasm

Question 6

tRNA

Answer 6

-binds + carries specific amino acids to the ribosome

Question 7

rRNA

Answer 7

along with proteins, make up the ribosome

Question 8

Transcription

Answer 8

DNA copied into a complementary strand made of mRNA
-Purpose: carry code/ instructions out of nucleus
-Location: nucleus
-Starts with: DNA
-Ends with: mRNA

Question 9

Process of Transcription

Answer 9

1. RNA Polymerase binds to DNA promoter where transcription is to begin and unzips gene that needs to be copied (TATA Box)
2. RNA polymerase uses complementary base-pairing rules to match RNA nucleotides with exposed DNA nucleotides (A+U and C+G)
3. Release mRNA molecule
4. DNA zips back up and mRNA leaves nucleus and enters cytoplasm

Question 10

RNA is made in the ________ direction

Answer 10

5’-3’ Direction

Question 11

The template is read in the _______ direction

Answer 11

3’-5’ direction

Question 12

Post-Transcription Modifications

Answer 12

-RNA Splicing: removes introns and splices exons together
-5’ Cap is added to the 5’ end (facilitates binding to a ribosome)
-Poly A tail is added to the 3’ end (helps mRNA leave nucleus

Question 13

Genetic Code

Answer 13

code of instructions for how to make proteins

Question 14

Codon

Answer 14

a set of 3 nucleotides on the mRNA

Question 15

Amino Acid

Answer 15

monomer for making proteins, held together by peptide bonds

Question 16

Anticodon

Answer 16

“complementary” 3 nucleotides on tRNA

Question 17

Translation

Answer 17

mRNA ——> polypeptide
Purpose: read instructions carried on mRNA to make a polypeptide
Location: Ribosomes
Starts with: mRNA
Ends with: Polypeptide

Question 18

Process of Translation

Answer 18

1. mRNA attaches to the small subunit of the ribosome
2. Ribosome reads the mRNA codons, always in the 5’-3’ direction, starting at the AUG codon (1 codon = 3 RNA nucleotides)
3. tRNAs act like taxis to pick up and drop off amino acids that match with each codon
4. tRNAs continue to drop off amino acids, and the ribosome binds the amino acids together with peptide bonds
5. when the “stop” codon is reached, the ribosome releases the completed polypeptide chain

Question 19

Regulation

Answer 19

gene expression is very regulated
-turning genes on and off is critical for cell differentiation
-transcription factors help

Question 20

Transcription factors

Answer 20

regulatory proteins that control gene activity
-Repressors: decrease transcription
-Activators: increase transcription

Question 21

Epigenetics

Answer 21

the study of changes in gene expression that are heritanle
-different from mutations
-dont affect actually DNA sequence, just how it is expresed
ex. Histone modification