DNA, Genes and Chromosomes

Question 1

what is a gene

Answer 1

the specific base sequence of DNa that codes for a specific polypeptide of functional RNA

Question 2

what is the gene locus?

Answer 2

the position of a gene on the chromosome

Question 3

which RNA is funcional?

Answer 3

tRNA
rRNA

Question 4

what is an allele?

Answer 4

various forms of a gene

Question 5

how many alleles are there for each gene in diploid organisms?

Answer 5

2

Question 6

heterozygous

Answer 6

different alleles for that gene on each chromosome

Question 7

homozygous

Answer 7

same alleles for that gene on each chromosome

Question 8

what is the nature and development of organisms determined by?

Answer 8

genes

Question 9

what does the sequence of bases in DNA determine?

Answer 9

the sequence of amino acids in a polypeptide

Question 10

what does the sequence of amino acids in a polypeptide determine?

Answer 10

shape and function of a protein

Question 11

what does the shape and function of a protein determine?

Answer 11

the characterists of a cell

Question 12

why is DNA associated around proteins

Answer 12

it is too long to fit in the cell so must be coiled and compacted into the cell

Question 13

is prokaryotic DNA longer or shorter than eukaryotic DNA?

Answer 13

shorter

Question 14

where is prokaryotic DNA present in eukaryotic cells?

Answer 14

in chloroplasts adn mitochondria

Question 15

karyotype

Answer 15

the number and type of chromosomes in a cell

Question 16

chromatin

Answer 16

double helix DNA wrapped around histones

Question 17

chromosome

Answer 17

condensed, super-coiled chromatin

Question 18

chromatid

Answer 18

1 strand of a replicated chromosome

Question 19

bivalent

Answer 19

a homologous pair of chromosomes that has replicated

Question 20

homologous chromosomes

Answer 20

2 chromosomes with the exact same genes in the exact same loci

Question 21

the genetic code

Answer 21

the sequence of bases along the length of DNA that determines the primary structure of a polypeptide

Question 22

how many amino acids are there?

Answer 22

20

Question 23

how many possible combinations of bases are there?

Answer 23

64

Question 24

degenerate

Answer 24

each triplet codes for one amino acid and each amino acid may have multiple triplets coding for it

Question 25

non-overlapping

Answer 25

each base is only read once/only part of one triplet

Question 26

universal (in terms of the genetic code)

Answer 26

the same triplet codes for the same amino acid in all organisms

Question 27

exons

Answer 27

sequences of mRNA bases that code for sequences of amino acids

Question 28

introns

Answer 28

sequences of mRNA bases that don’t code for sequences of amino acids

Question 29

what are introns made up of?

Answer 29

repeating sequence of 2 bases (CGCGCG etc.)

Question 30

genome

Answer 30

all the genes in the DNA of a cell/organism

Question 31

proteome

Answer 31

all the proteins that a cells’s genome can produce/code for

Question 32

3 bases in DNA

Answer 32

triplet

Question 33

3 bases on mRNA

Answer 33

codon

Question 34

3 bases on tRNA

Answer 34

anticodon

Question 35

what is mRNA

Answer 35

a single helical polynucleotide that carries the code that determines the sequence of amino acids in a polynucleotide chain

Question 36

relation between mRNA codons ad DNA base triplet

Answer 36

mRNA codons are complementary to DNA triplets

Question 37

what is tRNA?

Answer 37

a single-stranded polynucleotide folded into a clover leaf shape, which carries amino acids to ribosomes in translation

Question 38

how many different tRNA molecules are there?

Answer 38

61

Question 39

why are there less tRNA molecules than trriplet codons?

Answer 39

3 codons are stop codons, which do not code for amino acids