Genes And Chromosomes

Question 1

describe the DNA found in eukaryotic cells

Answer 1

linear DNA as chromosomes, long DNA, tightly wound and compacted, DNA is associated with histones

Question 2

describe the DNA found in prokaryotic cells

Answer 2

short, circular DNA, DNA condenses by being supercoiled, not wound around histones

Question 3

what is a gene?

Answer 3

a gene is a sequence of nucleotide bases Iona that codes for the sequence of amino acids that make up a particular polypeptide.

Question 4

what do genes that don’t code for a polypeptide code for?

Answer 4

functional RNA

Question 5

what is functional RNA?

Answer 5

a molecule other than mRNA eg tRNA which is involved in protein synthesis or rRNA which is used to make ribosomes

Question 6

what is an allele?

Answer 6

a different form of the same gene. The order of bases in each one is slightly different, so they code for slightly versions of the same polypeptide

Question 7

what are non coding sections of DNA called?

Answer 7

introns

Question 8

what are coding sections of DNA called?

Answer 8

exons

Question 9

what is an intron?

Answer 9

non coding section of DNA that are removed during protein synthesis

Question 10

what is an exon?

Answer 10

coding section/base of DNA that are copied for protein synthesis

Question 11

what are multiple repeats/variable tandem repeats?

Answer 11

repeating regions within the non coding regions of eukaryotic DNA

Question 12

define homologous chromosomes

Answer 12

matching chromosomes that have genes in the same place or locus but may have differing alleles

Question 13

what is a histone?

Answer 13

a protein that provides structural support for a chromosome

Question 14

describe the DNA in mitochondria and chloroplasts

Answer 14

circular and shorter and there is no histone

Question 15

what is the genome?

Answer 15

the complete set of genes in a cell

Question 16

what is the proteome?

Answer 16

the full range of proteins a cell is able to produce

Question 17

what is the locus on a chromosome?

Answer 17

the location of the genes on the chromosome

Question 18

give 2 ways in which prokaryotic DNA is different from eukaryotic DNA

Answer 18

1. eukaryotic is linear, prokaryotic is short and circular
2. prokaryotic isn’t associated with histones eukaryotic is

Question 19

Describe how a gene is a code for the production of a polypeptide

Answer 19

because the base sequence which is in triplets determines the order of amino acids

Question 20

define “non coding regions” and describe where the non-coding multiple repeats are positioned in the genome

Answer 20

DNA that doesn’t code for proteins, between genes