biology exam revision

DNA and genetics

DNA is an acronym for?

deoxyribonucleic acid

which of the following is a component of a DNA nucleotide?

phosphate group

circle = phosphate pentagon = phosphate sugar rectangle = nucleotide base

how many chromosomes do humans typically have?

46

what is the function of DNA?

to carry genetic materials

what is the term describing a change to the DNA sequence?

mutation

which of the following best describes chromosomes?

a tightly coiled stand of DNA

what is the complementary strand to: ATCGG

TAGCC

which of the following is true about gene?

gene is a section of a chromosome

what is the correct order?

DNA → genes → chromosomes

use a diagram, describe the relationship between DNA, chromosomes and genes.

DNA is a double helix structure made up of nucleotides containing a sugar phosphate backbone and a nucleotide base. Chromosomes are structures made up of a single long coiled strand of DNA. A gene is a specific sequence of DNA bases that codes for different proteins, which is located on different parts of a chromosome.

what is the purpose of DNA replication?

to ensure each new cells has a complete set of DNA

DNA is described as semi-conservative because

each new DNA molecule contains one old strand and one new strand

the number of chromosomes in daughter cells compared to parent cell at the end of mitosis are

same (mitosis is the identical replication of their offspring)

the purpose of meiosis is:

to produce gametes with half the number of chromosomes

what is the term for different versions of the same gene?

alleles

if an organism has two identical alleles for a trait, it is called:

homozygous

The gene for black coat (B) cat is dominant over brown coat (b). If a black coat (Bb) male cat was crossed with a brown coat (bb) female, what will be the predicted percentage of offsprings with brown coat?

50%

what is genotype?

an organisms full genetic makeup and all the alleles inherited from both parents

what is phenotype?

the observable, physical traits of those genes we can see

white flowers are dominant (F) over purple flowers (f). the phenotype of a flower with a genotype Ff is:

white flower