RNA and Protein Synthesis

Question 1

What is the role of DNA in genetic material?

Answer 1

DNA contains a code that living cells can read, understand, and express.

Question 2

What are the four nucleotides that make up DNA?

Answer 2

The four nucleotides are adenine (A), thymine (T), cytosine (C), and guanine (G).

Question 3

What role does RNA play in relation to DNA?

Answer 3

RNA helps to put the genetic code into action by directing the production of proteins.

Question 4

What are the structural differences between RNA and DNA?

Answer 4

RNA uses ribose sugar, is generally single-stranded, and contains uracil instead of thymine.

Question 5

What is the function of genes?

Answer 5

Genes contain coded DNA instructions that tell cells how to build proteins.

Question 6

What is transcription?

Answer 6

Transcription is the process of copying a base sequence from DNA into RNA.

Question 7

What is the role of RNA polymerase?

Answer 7

RNA polymerase carries out transcription by producing complementary RNA molecules.

Question 8

What are introns?

Answer 8

Introns are portions of pre-mRNA that are cut out and discarded before the RNA can go into action.

Question 9

What is a codon?

Answer 9

A codon is a three-base sequence in mRNA that specifies a single amino acid.

Question 10

How many possible codons are there in the genetic code?

Answer 10

There are 64 possible three-base codons in the genetic code.

Question 11

What is a start codon?

Answer 11

The start codon is AUG, which initiates protein synthesis.

Question 12

What is the role of ribosomes in protein synthesis?

Answer 12

Ribosomes assemble amino acids into polypeptide chains using the sequence of codons in mRNA.

Question 13

What is the function of messenger RNA (mRNA)?

Answer 13

mRNA carries copies of instructions from the nucleus to ribosomes in the cytoplasm.

Question 14

What is the function of transfer RNA (tRNA)?

Answer 14

tRNA carries amino acids to the ribosome and matches them to the coded mRNA message.

Question 15

What is the significance of the TATA box in eukaryotic gene regulation?

Answer 15

The TATA box helps position RNA polymerase by marking a point just before the beginning of a gene.

Question 16

What is the lac operon?

Answer 16

The lac operon is a cluster of genes in E. coli that must be turned on together to break down lactose.

Question 17

How does the lac repressor function?

Answer 17

The lac repressor binds to the operator region to prevent transcription of the lac genes when lactose is not present.

Question 18

What is the role of transcription factors in gene regulation?

Answer 18

Transcription factors help regulate gene expression by opening chromatin or blocking access to certain genes.

Question 19

What are homeotic genes?

Answer 19

Homeotic genes are master control genes that regulate the identities of body parts in an embryo.

Question 20

Who was the first to show that a specific group of genes controls body part identities in fruit fly embryos?

Answer 20

American biologist Edward B. Lewis.

Question 21

What happens if one of the homeotic genes is changed?

Answer 21

A body part like an antenna might be changed into a leg.

Question 22

What are homeotic genes?

Answer 22

A set of master control genes that regulates organs developing in specific body parts.

Question 23

What is the homeobox?

Answer 23

A very similar 180-base DNA sequence shared by homeotic genes.

Question 24

What do homeobox genes code for?

Answer 24

Transcription factors that activate other genes important in cell development and differentiation.

Question 25

What are Hox genes?

Answer 25

A group of homeobox genes in flies that determine the identities of each segment of a fly's body.

Question 26

How are Hox genes arranged?

Answer 26

In the exact order in which they are expressed, from anterior to posterior.

Question 27

What determines the basic body structure in fruit flies?

Answer 27

A series of Hox genes along a chromosome.

Question 28

Do mice have Hox genes?

Answer 28

Yes, mice have similar genes on four different chromosomes.

Question 29

Do clusters of Hox genes exist in other animals?

Answer 29

Yes, including humans.

Question 30

What is the role of nucleosomes in gene regulation?

Answer 30

Nuclear DNA is coiled around nucleosomes to form chromatin, affecting gene expression.

Question 31

How do chemical marks influence chromatin structure?

Answer 31

They determine how compact chromatin is in a given region of DNA.

Question 32

What are epigenetic marks?

Answer 32

Chemical marks on chromatin that influence gene expression without changing DNA base sequences.

Question 33

What is an example of environmental impact on gene expression?

Answer 33

The coloring of the coat of a Himalayan rabbit.

Question 34

What was observed in Dutch children born post-WWII?

Answer 34

They had higher rates of obesity, diabetes, and cardiovascular disease than their parents.

Question 35

What happens to the fur color of Himalayan rabbits at different temperatures?

Answer 35

At temperatures between 15°C and 25°C, the gene produces black fur; above 30°C, the gene is inactive and the rabbit is white.

Question 36

What are mutations?

Answer 36

Heritable changes in genetic information caused by mistakes in DNA copying.

Question 37

What are point mutations?

Answer 37

Mutations that change a single base pair in the DNA sequence.

Question 38

What is a silent mutation?

Answer 38

A point mutation that does not affect the amino acid sequence.

Question 39

What is a missense mutation?

Answer 39

A mutation that changes the amino acid specified by a codon.

Question 40

What is a nonsense mutation?

Answer 40

A mutation that creates a stop codon, resulting in incomplete protein synthesis.

Question 41

What are insertions and deletions?

Answer 41

Mutations where bases are added or removed from the DNA sequence.

Question 42

What are chromosomal mutations?

Answer 42

Mutations that involve changes in the number or structure of chromosomes.

Question 43

What are the four types of chromosomal mutations?

Answer 43

Deletion, duplication, inversion, and translocation.

Question 44

What can cause mutations?

Answer 44

Errors in genetic processes and mutagens.

Question 45

What are mutagens?

Answer 45

Chemical or physical agents that can cause mutations.