Genetics- DNA Exam

Question 1

What is the difference between DNA and RNA (MC)

Answer 1

DNA is double-stranded, forming a double helix, while RNA is usually single-stranded.

Question 2

What is the base unit of DNA? (MC)

Answer 2

The bases used in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T). (Nucleotide)

Question 3

What are the three types of RNA and what are their roles? (MC)

Answer 3

mRNA (messenger RNA): it provides the template for protein synthesis during translation.

tRNA (transfer RNA): it brings amino acids and reads the genetic code during translation.

rRNA (ribosomal RNA): it plays a structural and catalytic role during translation.

Question 4

Purpose of DNA replication (MC)

Answer 4

The purpose of DNA replication is to produce two identical copies of a DNA molecule.

Question 5

Where does DNA replication occur? (MC)

Answer 5

DNA replication occurs in the nucleus in eukaryotic cells and in the nucleoid in prokaryotic cells.

Question 6

What does semi-conservative mean? (MC)

Answer 6

Half conserved or relating to or denoting replication of a nucleic acid in which one complete strand of each double helix is directly derived from the parent molecule.

Question 7

Describe the steps of DNA replication including lagging and leading strand (MC)

Answer 7

one new strand (the leading strand) is made as a continuous piece. The other (the lagging strand) is made in small pieces

Question 8

What are the parts of the DNA molecule? (MC)

Answer 8

a nitrogenous base, a five-carbon sugar (deoxyribose), and a phosphate group. There are four nitrogenous bases in DNA, two purines (adenine and guanine) and two pyrimidines (cytosine and thymine).

Question 9

What are the nucleotide pairings of DNA mRNA and tRNA (MC + SHORT)

Question 10

Use mRNA codons to find the correct amino acid sequences

Question 11

What is the purpose of the DNA polymerase? (MC)

Answer 11

The primary role of DNA polymerases is to accurately and efficiently replicate the genome in order to ensure the maintenance of the genetic information and its faithful transmission through generations.

Question 12

What is proteins synthesis? (MC)

Answer 12

Protein synthesis is the process by which ribosomes read and process mRNA to make a protein.

Question 13

Where does transcription occur? (MC)

Answer 13

in the nucleus of the cell.

Question 14

Describe the steps of transcription (MC)

Answer 14

Transcription has three stages: initiation, elongation, and termination.

Initiation starts it

elongation is the stage when the RNA strand gets longer, thanks to the addition of new nucleotides.

Termination ends it

Question 15

Where does translation occur? (MC)

Answer 15

Ribosome

Question 16

Describe the steps of translation, including tRNA, and amino acids (MC)

Answer 16

During translation, these tRNAs carry amino acids to the ribosome and join with their complementary codons. Then, the assembled amino acids are joined together as the ribosome, with its resident rRNAs, moves along the mRNA molecule in a ratchet-like motion.

Question 17

What is the difference between a codon and an anti-codon? (SHORT)

Answer 17

A codon is a three-nucleotide or triplet sequence found on mRNA that codes for a certain amino acid during translation. The anticodon is a three-nucleotide sequence found on tRNA that binds to the corresponding mRNA sequence.

Question 18

What is the difference between helicase, polymerase and ligase? (SHORT)

Answer 18

Helicase unwinds the DNA double helix, polymerase adds new nucleotides to the growing DNA strand during replication, and ligase seals the gaps in the sugar-phosphate backbone to complete the process.

Question 19

What is the difference between mRNA and tRNA? (SHORT)

Answer 19

mRNA provides a template for gene coding during protein synthesis, tRNA carries the amino acids to the ribosomes, which has to be added to the polypeptide chain

Question 20

What is the difference between pyrimidines and purines? (SHORT)

Answer 20

Purines have a double-ring structure and consist of adenine and guanine, while pyrimidines have a single-ring structure and consist of cytosine, thymine, and uracil.

Question 21

What is a genetic mutation? (MC)

Answer 21

a change in one or more genes. Some mutations can lead to genetic disorders or illnesses.

Question 22

What is translocation? (MC)

Answer 22

A genetic change in which a piece of one chromosome breaks off and attaches to another chromosome.

Question 23

What is deletion? (MC)

Answer 23

A type of genetic change that involves the absence of a segment of DNA.

Question 24

What is inversion? (MC)

Answer 24

An inversion in a chromosome occurs when a segment breaks off and reattaches within the same chromosome, but in reverse orientation.

Question 25

What is duplication? (MC)

Answer 25

refers to a type of mutation in which one or more copies of a DNA segment (which can be as small as a few bases or as large as a major chromosomal region) is produced.

Question 26

What is a frame shift mutation? (MC)

Answer 26

the insertion or deletion of nucleotide bases in numbers that are not multiples of three.

Question 27

How do genetic mutations influence evolution? (SHORT)

Answer 27

Mutations are one of the fundamental forces of evolution because they fuel the variability in populations and thus enable evolutionary change.