Week 5 Y

Question 1

What are the main components of DNA structure?

Answer 1

DNA consists of a nucleotide base (A, T, C, G), a deoxyribose sugar, and a phosphate backbone, forming a double helix stabilized by hydrogen bonds between complementary bases.

Question 2

Why does DNA form a helical structure?

Answer 2

which help DNA form and maintain its helical shape.

Question 3

What is the role of RNA polymerase in transcription?

Answer 3

RNA polymerase binds to DNA with the help of a sigma factor, which recognizes the promoter region and initiates transcription by synthesizing mRNA.

Question 4

Operon

Answer 4

cluster of genes transcribed together from a single promoter, allows coordinated gene expression

Question 5

codon

Answer 5

a sequence of three nucleotide bases on mRNA that codes for a specific amino acid or signals start or stop in protein synthesi

Question 6

What is the difference between inducible and constitutive genes?

Answer 6

Inducible genes are turned on or off based on environmental conditions, while constitutive genes are always expressed as they are essential for cell function.

Question 7

sigma factors

Answer 7

proteins that help RNA polymerase recognize promoter regions on DNA, initiating transcription.

Question 8

Name the three main types of RNA and their functions.

Answer 8

mRNA (messenger RNA) carries the genetic code, rRNA (ribosomal RNA) forms the ribosome, and tRNA (transfer RNA) brings amino acids to the ribosome during translation.

Question 9

promoter

Answer 9

DNA sequence where RNA polymerase binds to initiate transcription of a gene or operon.

Question 10

plasmids

Answer 10

small, circular DNA molecules that exist independently of the bacterial chromosome and can carry additional genes, often including those for antibiotic resistance

Question 11

Main steps in transcription

Answer 11

Initiation (RNA polymerase binds to promoter), Elongation (RNA is synthesized), and Termination (RNA polymerase releases the newly formed mRNA).

Question 12

function do ribosomes serve in translation?

Answer 12

reading mRNA codons and binding tRNAs with corresponding anticodons.

Question 13

Induced mutations

Answer 13

Induced mutations include chemical mutations (analogous bases, intercalating agents, base modifications) and physical mutations (e.g., UV light causing thymine dimers)

Question 14

DNA polymerase role

Answer 14

DNA polymerase has proofreading abilities that reduce errors during DNA replication

Question 15

Four types of mutations

Answer 15

nonsense mutations, missense mutations, frameshift mutations, and silent mutations.

Question 16

Non sense mutation

Answer 16

introduces a premature stop codon, leading to nonfunctional proteins.

Question 17

Missense mutation

Answer 17

a change in a single amino acid in the protein, which can affect protein function.

Question 18

Frameshift mutation

Answer 18

the insertion or deletion of nucleotides, which shifts the reading frame of the genetic code, potentially altering all downstream amino acids.

Question 19

Silent mutation

Answer 19

changes a nucleotide but does not alter the amino acid sequence of the protein, typically having no impact on protein function.

Question 20

Vertical gene transfer

Answer 20

the transmission of genetic material from a parent cell to its daughter cells during reproduction.

Question 21

Horizontal gene transfer

Answer 21

Horizontal gene transfer is the transfer of genetic material between mature cells

Question 22

Name the three major mechanisms of horizontal gene transfer in bacteria

Answer 22

transformation, transduction, and conjugation.

Question 23

Transformation

Answer 23

the uptake of free, extracellular DNA by a bacterium, often by naturally competent bacteria such as Bacillus subtilis and Streptococcus pneumoniae.

Question 24

Transduction

Answer 24

the process by which DNA is accidentally transferred from one bacterium to another by a bacteriophage (virus).

Question 25

Conjugation

Answer 25

the transfer of DNA, often plasmids, between bacteria through direct contact using a pilus. This can transfer either plasmid or chromosomal DNA.

Question 26

Origin of transfer

Answer 26

the sequence on a plasmid that marks the starting point for DNA transfer between bacteria.

Question 27

Genes

Answer 27

Functional unit of information

Question 28

3 types of rna and their role

Answer 28

mRNA - Carries info from dna -> ribosome

tRNA - Converts genetic information into AA’s

rRNA - Catalytic components in ribosomes

Question 29

Chromosome

Answer 29

contains genetic material

Question 30

Plasmids

Answer 30

Double stranded DNA molecules

Question 31

Denaturation

Answer 31

Loss of protein structure

Question 32

Ribosome

Answer 32

Site of protein synthesis