U4 T1 - DNA, Genes,

Question 1

What is deoxyribonucleic acid (DNA)?

Answer 1

It is a double-stranded molecule that occurs bound to proteins (histones) in chromosomes in the nucleus

Question 2

What are the four bases in DNA?

Answer 2

Adenine, Thymine, Guanine and Cytosine

Question 3

What is the structure of DNA?

Answer 3

It is a double helix formed with two complementary strands of nucleotides held together by hydrogen bonds between G-C and A-T base pairs.

Question 4

What role does helicase play in DNA?

Answer 4

They separate double-stranded DNA into single strands allowing each strand to be copied.

Question 5

What happens in Meiosis I?

Answer 5

Homologue pairs separate during a first round of cell division,

Question 6

What happens in Meiosis II?

Answer 6

Sister chromatids separate during a second round

Question 7

How does the process of crossing over and recombination contribute to genetic variation?

Answer 7

Homologous chromosomes – 1 inherited from each parent – pair along their lengths, gene by gene.

Question 8

Define the term genome

Answer 8

The haploid set of chromosomes in a gamete

Question 9

Define the term Gene

Answer 9

Genes are made up of sequences of DNA which are the basic unit of heredity information passed from parent to child.

Question 10

What do gene’s include?

Answer 10

coding and noncoding DNA, functional RNA, centromeres, telomeres and introns

Question 11

explain the process of protein synthesis

Answer 11

transcription of a gene into messenger RNA in the nucleus ­translation of mRNA into an amino acid sequence at the ribosome

Question 12

What is the purpose of gene expression?

Answer 12

It is to synthesise a functional gene product (protein or functional RNA)

Question 13

What are the factors that regulate the phenotypic expression of genes during transcription?

Answer 13

Transcription factors which bind to specific DNA sequences and regulate gene expression.

Question 14

What does differential gene expression do to cell differentiation?

Answer 14

It regulates cell differentiation for tissue formation and morphology

Question 15

Example of a transcription factor that regulates morphology

Answer 15

HOX transcription factor family

Question 16

How can mutations in genes and chromosomes can result from errors in ­ DNA replication?

Answer 16

It can cause cell division and damage mutagens

Question 17

Explain how non-disjunction leads to aneuploidy

Answer 17

It is from the failure of the sister chromatids to separate during anaphase II

Question 18

describe how inherited mutations can alter the variations in the genotype of offspring.

Answer 18

The mutations cause changes in the proteins produced, and therefore it’s structure or function

Question 19

Define polygenic inheritance

Answer 19

Polygenic inheritance refers to the inheritance of a trait governed by more than one genes.

Question 20

Describe the process of making recombinant DNA

Answer 20

isolation of DNA, cutting of DNA (restriction enzymes) ­ insertion of DNA fragment (plasmid vector) ­ joining of DNA (DNA ligase) ­ amplification of recombinant DNA (bacterial transformation)

Question 21

What are the applications of DNA sequencing

Answer 21

to find genes, segments of DNA that code for a specific protein or phenotype

Question 22

Explain the purpose of polymerase chain reaction (PCR) and gel electrophoresis

Answer 22

the goal of PCR is to make enough of the target DNA region that it can be analyzed or used in some other way.

Question 23

Explain Interphase

Answer 23

The cells are growing and chromosomes are duplicated in preparation for cell division

Question 24

Explain Prophase

Answer 24

The chromosomes condense making them easier to pull apart. The nuclear membrane dissolves freeing the chromosomes

Question 25

Explain Metaphase

Answer 25

Short resting phase wherethechromosomes line up on theequator of the cell. Centrosomes are now at oppositeends with spindle fibers attachedto the centromeres

Question 26

Explain Anaphase

Answer 26

The centromeres divide - spindle fibers contractand chromosomespull toopposite poles

Question 27

Explain Telophase

Answer 27

The nuclear envelope that hadbroken down reforms around eachof the new sister chromatids

Question 28

Explain Prophase II

Answer 28

In each of the daughter cells, a new spindle apparatus forms, the nuclear envelope breaks down, and the chromatin condenses into chromosomes again.

Question 29

Explain Metaphase II

Answer 29

The chromosomes line up along the metaphase plate.

Question 30

Explain Anaphase II

Answer 30

Separation of the sister chromatids occur in this phase

Question 31

Explain Telophase II

Answer 31

The chromosomes gather at the 2 poles of the cell and the cell divides via cytokinesis forming 2 daughter cell