DNA Genes and Chromosomes

Question 1

What are the levels of DNA structure smallest to largest

Answer 1

Nucleotide-Nucleic acid-Gene-Chromosome

Question 2

Describe DNA in eukaryotic cells

Answer 2

Long, linear DNA molecules
Highly coiled
Combine with histones to form chromatin
One chromosome contains one DNA molecule

Question 3

Describe DNA in prokaryotic cells

Answer 3

short circular DNA
Not associated with proteins

Question 4

What structures contain DNA in a eukaryotic cell

Answer 4

Nucleus
Chloroplasts
Mitochondria

Question 5

Describe DNA in mitochondrias and chloroplasts

Answer 5

Short circular DNA
Not associated with proteins

Question 6

Compare Eukaryotic and prokaryotic dna

Answer 6

Prokaryotic is short circular and doesn’t associate with proteins
Eukaryotic is long, linear and coiled but associates with proteins

Question 7

How do chromosomes in eukaryotic cells appear

Answer 7

Two threads joined at the centromere
Each thread is a chromatid and identical meaning they are referred to as sister chromatids

Question 8

What are diploid cells

Answer 8

Where chromosomes are found in pairs

Question 9

What are haploid cells

Answer 9

Where chromosomes are not found in pairs

Question 10

How many chromosomes do diploid cells have

Answer 10

46 chromosomes
23 pairs

Question 11

How many chromosomes do haploid cells have

Answer 11

23 chromosomes

Question 12

What are chromosomes made up of

Answer 12

A single DNA molecule with many genes along its length

Question 13

What is a gene

Answer 13

A small section of DNA which codes for a particular protein

Question 14

What is a locus

Answer 14

A specific position a gene occupies

Question 15

What is an allele

Answer 15

a different form of a particular gene

Question 16

What is a gamete

Answer 16

A sex cell

Question 17

What is a dominant allele

Answer 17

only 1 copy of the allele required for it to be expressed in the phenotype

Question 18

What is a recessive allele

Answer 18

2 copies required for the allele to be expressed in the phenotype

Question 19

What is a genotype

Answer 19

the 2 alleles an individual possesses for a particular gene

Question 20

What is a phenotype

Answer 20

the physical characteristics displayed by the individual resulting from genotype and environment

Question 21

What is a homozygous pair

Answer 21

having 2 of the same allele for a gene (2 dominant or 2 recessive)

Question 22

What is a heterozygous pair

Answer 22

having 2 different alleles for a gene (1 dominant and 1 recessive )

Question 23

What do Non-coding DNA do

Answer 23

Non-coding DNA does not code for any amino acids

Question 24

Where can non-coding DNA be found

Answer 24

between genes as the same base sequence repeated a number of times
Within genes as introns

Question 25

What are nucleic acids

Answer 25

Information carrying molecules which are found in all living cells

Question 26

What are two types of nucleic acid

Answer 26

RNA and DNA

Question 27

What is DNA made up of

Answer 27

A phosphate group A deoxyribose sugar An organic base

Question 28

Describe the structure of DNA

Answer 28

A phosphate group joined to a deoxyribose sugar at its C5 An organic base attached to a deoxyribose sugar at C1

Question 29

What are the 4 Nitrogenous bases

Answer 29

Adenine Thymine Guanine Cytosine

Question 30

What are the purine bases

Answer 30

Adenine and Thymine

Question 31

What are the pyrimidine bases

Answer 31

Guanine and Cytosine

Question 32

How do chromosomes appear under a microscope

Answer 32

An X shape

Question 33

Why is DNA well adapted

Answer 33

Sugar phosphate backbone held by covalent bonds Complementary base pairing allows it to be copied Tightly coiled structure allows lots of information in a small space

Question 34

What bonds are present in a DNA nucleotide

Answer 34

Phosphodiester bond

Question 35

What is a karyotype

Answer 35

Shows the full structure of chromosomes present in an organism

Question 36

Define the structure of DNA

Answer 36

double-stranded helix held together by complementary base pairs