DNA, genes and chromosomes

Question 1

DNA in eukaryotic cells

Answer 1

large, linear, associated with histones, form chromosomes

Question 2

DNA in prokaryotic cells

Answer 2

short, circular, not associated with proteins, don’t have chromosomes

Question 3

DNA in mitochondria and chloroplasts

Answer 3

short, circular, not associated with histones

Question 4

chromosome

Answer 4

found in nucleus, chromosomes carry genes, made up of large molecules of DNA

Question 5

gene

Answer 5

section of DNA on a chromosome that controls a feature by coding for the formation of a specific protein

Question 6

allele

Answer 6

alternative forms of a particular gene with different base sequences, therefore different codes coding for different versions of the same protein

Question 7

structure of chromosomes

Answer 7

-DNA combined with histones (nucleosomes)
-DNA-histone complex is coiled (chromatin)
-coils fold to form a loop
-loops coil and pack together to form a chromosome
-only visible during mitosis
-appear as two threads (chromatids) joined by a centromere

Question 8

locus

Answer 8

gene always occurs at the same position on each chromosome

Question 9

karyotype

Answer 9

full chromosome complement of a cell and illustrate the number, size and shape of the chromosomes

Question 10

triplet code

Answer 10

3 bases=1 amino acid

Question 11

degenerate code

Answer 11

most amino acids are coded for by more than one triplet

Question 12

non overlapping code

Answer 12

each base appears in only one triplet, only read each base once

Question 13

universal code

Answer 13

same codon codes for the same amino acid in all living things