[Maximum number: 1]
Whole genome sequencing has allowed scientists to compare the genetic content of different organisms. The table shows the genome sizes of some plants and animals.
(a)
State one organelle in which a base pair could be found.
[ 1 ]
[Maximum number: 4]
The image of a nucleosome was obtained using molecular visualization software.
(a)
(i)
Adenine forms hydrogen bonds with the nitrogenous base X . Identify X .
[ 1 ]
(b)
Describe the structure of the nucleosome.
[ 3 ]
[Maximum number: 1]
Which of the following describes the molecular structure of DNA?
I. Complementary base pairing occurs within the molecule
II. Contains deoxyribose
III. Contains thymine
A
I and II only
B
I and III only
C
II and III only
D
I, II and III
[Maximum number: 1]
What is "naked DNA"?
A
DNA not surrounded by a nuclear envelope
B
DNA that is single-stranded due to heat treatment
C
DNA not associated with proteins
D
DNA not super-coiled into chromosomes
[Maximum number: 1]
The image shows a DNA nucleotide.
Which correctly identifies the parts labelled I and II?
I
II
base
phosphate
ribose
uracil
deoxyribose
base
ribose
adenine
[Maximum number: 1]
What allows DNA to store very large amounts of data?
A
Two strands of DNA
B
Base sequence
C
Complementary base pairing
D
Sugar-phosphate backbone
[Maximum number: 1]
Hershey and Chase used bacteriophages to investigate the chemical nature of genes. The phosphorus in the DNA and the sulphur in the protein of the bacteriophages were radioactively labelled.
The data obtained after the infection and then centrifugation of bacterial cells is shown in the table.
What did Hershey and Chase conclude from their experiment?
A
Viral DNA was found within the bacterial cells.
B
Viruses infect bacterial cells with proteins.
C
DNA was mainly outside the bacterial cells.
D
Neither protein nor DNA were chemicals making up genes in viruses.
[Maximum number: 1]
The diagram shows a structure found in a eukaryotic nucleus.
What is represented by X and Y ?
X
Y
Ribosome
mRNA
Histone
Linker DNA
Nucleosome
mRNA
RNA polymerase
Linker DNA
[Maximum number: 1]
What is a nucleosome?
A
DNA wrapped around histone proteins in a eukaryotic cell
B
RNA bound to ribosomes in a eukaryotic cell
C
A region of the nucleus in a eukaryotic cell
D
Genetic material within a viral capsule
[Maximum number: 1]
What usually distinguishes DNA from RNA?
DNA
RNA
strands are symmetrical
strands are antiparallel
contains adenine
contains cytosine
pentoses linked to phosphates
pentoses linked to bases
double stranded
single stranded