Genes, Proteins, and Cell Division

Question 1

Making a mRNA copy of a gene is known as what?

Answer 1

Transcription.

Question 2

What a the 3 main parts of a gene?

Answer 2

The promotor, the coding sequence, and the the terminator.

Question 3

The process of producing a protein from mRNA is known as what?

Answer 3

Translation.

Question 4

Which strand of DNA is used to make mRNA?

Answer 4

The template strand.

Question 5

Before mRNA can be translated into proteins, what must happen?

Answer 5

It must be processed, i.e.Introns must be removed by splicing.

Question 6

What is a codon?

Answer 6

A sequence of 3 base pairs that codes for an amino acid.

Question 7

What is meant by the genetic code?

Answer 7

The 4 letter code of DNA can represent 20 different amino acids by different combinations in a codon, i.e. there are 64 possible combinations.

Question 8

Codons in mRNA are recognised by anticodons on what molecule?

Answer 8

tRNA.

Question 9

What are the 3 steps in translation?

Answer 9

Initiation, elongation, termination.

Question 10

What are the phases of the cell cycle?

Answer 10

Growth 1 (G1), Syntheses (S), Growth 2 (G2), Mitosis (M).

Question 11

During which phase is DNA replicated?

Answer 11

The S phase.

Question 12

During which phase are organelles duplicated?

Answer 12

G1 phase.

Question 13

What is meant by semi-conservative replication?

Answer 13

Each new double stranded DNA contains half of the old strand of DNA.

Question 14

What are the stages of mitosis?

Answer 14

Prophase, metaphase. anaphase. and telephase.

Question 15

The nuclear envelope disappears in what stage?

Answer 15

Prophase.

Question 16

During anaphase the 2 sister chromatids are pulled apart by attaching to what?

Answer 16

Microtubules of the mitotic spindle.

Question 17

What are the 3 fates of a cell?

Answer 17

1. To remain alive and functioning without dividing.
2. To grow and divide.
3. To die.

Question 18

What is the importance of checkpoints in the cell cycle.

Answer 18

To halt division if conditions are not right, e.g. if the DNA hasn’t been copied properly or there are not enough nutrients.

Question 19

What is the difference between apoptosis and necrosis?

Answer 19

Apoptosis is programmed cell death and doesn’t disrupt surrounding cells, necrosis is uncontrolled cell death that harms surrounding cells due to spillage of cell contents.

Question 20

How many chromosome pairs do humans have?

Answer 20

23.

Question 21

A variant of a gene is known as what?

Answer 21

An allele.

Question 22

When an individual has 2 identical alleles of the same gene they are said to be what?

Answer 22

Homozygous.

Question 23

What does it mean when a cell is duploid or haploid?

Answer 23

Duploid means 2 copies of each chromosome, haploid means only one copy.

Question 24

What is a trait?

Answer 24

An observable feature of an organism, e.g. eye colour.

Question 25

What is meant be a dominant trait?

Answer 25

Only one copy of the gene is needed for the trait to appear.

Question 26

What is the difference between phenotype and genotype.

Answer 26

A phenotype is the observable end-product of genes, i.e. a trait, while a genotype is the genetic sequence itself.

Question 27

If parents are heterozygous for a certain gene, i.e. they both have a dominant B gene and a recessive b gene, what is the probability of a child being homozygous for the recessive trait?

Answer 27

25%

Question 28

What is meant by a homologous gene or chromosome?

Answer 28

They code for the same proteins, even though there may be variance in the exact sequence.

Question 29

What is the law of segregation?

Answer 29

Genes pairs are transferred to gametes with equal probability.

Question 30

What is the law of independent assortment?

Answer 30

Each gene is transferred to a gamete independently of others, i.e. the probability of gene A being transferred to the gamete does not affect the probability of the B gene being transferred, as long as they're on different chromosomes.

Question 31

What can we use to trace a trait from a family history?

Answer 31

A pedigree chart.

Question 32

What kind of inheritance pattern does this pedigree chart show?

Answer 32

Autosomal dominant. The trait is found in every generation and affects both sexes equally.

Question 33

What inheritance pattern does this chart show?

Answer 33

Autosomal recessive. Two unaffected parents gave an affected child and it affects both sexes equally.