EXAM 4-2

Question 1

DNA is a polymer – what is the monomer that DNA is made of?

Answer 1

nucleotides

Question 2

What are the three parts of every nucleotide?

Answer 2

sugar, a phosphate, and a nitrogen base

Question 3

What are the four nitrogen bases in DNA?

Answer 3

– Adenine (A)
– Cytosine (C)
– Guanine (G)
– Thymine (T)

Question 4

What are the base pairing rules for DNA?

Answer 4

A – T, and G – C

Question 5

How does DNA replication occur?

Answer 5

a cell copies its DNA to ensure that each daughter cell receives an identical copy during cell division.

Question 6

What does DNA have the instructions for making?

Answer 6

instructions for making proteins

Question 7

What is a gene?

Answer 7

one section of DNA

Question 8

What are the two main steps in protein synthesis?

Answer 8

transcription (DNA to mRNA) and translation (mRNA to protein)

Question 9

Explain what happens in transcription (and where in a cell this occurs).

Answer 9

• genetic information encoded in DNA is copied into a complementary mRNA sequence
• It takes place in the nucleus in eukaryotic cells.

Question 10

How are the base pairing rules for RNA different from the base pairing rules for DNA?

Answer 10

DNA Base Pairing:
Adenine (A) pairs with Thymine (T).
Cytosine (C) pairs with Guanine (G).

RNA Base Pairing:
Adenine (A) pairs with Uracil (U) (instead of Thymine).
Cytosine (C) pairs with Guanine (G

Question 11

What messenger RNA (mRNA) sequence would be made from this strand of DNA?
AAT GCA CAG TTA

Answer 11

UUA CGU GUC AAU

Question 12

What is the “protein factory” called?

Answer 12

a ribosome [translation]

Question 13

Explain what happens in translation. And what role does tRNA play in translation?

Answer 13

• Translation is the process of turning the mRNA code into a protein.
• tRNA matches the mRNA codons with the correct amino acids, ensuring the assembly of the polypeptide chain.

Question 14

What is a mutation?

Answer 14

any change in the sequence of nucleotides in DNA molecules, due to a
mistake in DNA replication (copying)

Question 15

What is the difference between a base substitution mutation, and an addition or deletion
mutation?

Answer 15

Base Substitution Mutation- one letter (nucleotide) in the DNA is swapped for another.

Addition or Deletion Mutation-
one or more letters are added or removed from the DNA.

Question 16

Why does a base addition or deletion always change the amino acid sequence?

Answer 16

• it shifts the reading frame of the genetic code. (frameshift mutation).

Question 17

One possible effect of a mutation is that it could be neutral (no change). What are the other
two possible effects, which one is more common, and why is it more common?

Answer 17

Neutral mutations, benificial mutation and harmful mutation.

Neutral mutations are the most common because mutations occur in non-coding regions of DNA or result in changes that don’t affect the protein’s function (like silent mutations).

Question 18

What are STR’s, and how can they be used to identify someone?

Answer 18

STRs are short, repetitive DNA sequences that create a unique DNA profile for an individual with STR loci
- forensics, paternity testing, and genetic identification

Question 19

List 2 reasons why we might test someone’s DNA

Answer 19

Paternity or Family Relationship Testing
Forensic Identification

Question 20

List 3 ways that we use genetic engineering to improve our lives.

Answer 20

Improved Crops and Agriculture
Medical Treatments and Therapies
Environmental Applications

Question 21

What is CRISPR, and (basically) how does it work?

Answer 21

CRISPR is editing genes by cutting DNA at specific points to making changes.

• good for research, medicine, and potentially treating genetic disorders.