Question 1
Question
The largest organelle in a cell is the ____ .
Answer
-
Nucleus
-
Mitochondria
-
Cytoplasm
-
Plasma membrane
Question 2
Question
The first thing to divide during cell division is the ____ which controls and directs the activities of the cell throughout life; it contains the ____ which is passed from generation to generation during reproduction.
Question 3
Question
Each ____ consists of ____, a huge molecule consisting of 2 ____ strands in the form of a double helix which runs ____ of the chromosome and is supported by ____ .
Answer
-
Chromosome | DNA | paired | the full length | protein
-
Chromosome | DNA | separate | for half | histones
-
Chromatid | DNA | linked | the full length | protein
Question 4
Question
A pair of genes with the same alleles are called ____ .
Answer
-
Homozygous
-
Heterozygous
-
Homologous
Question 5
Question
When the ____ chromosomes have paired up closely, each pair is called a ____.
Answer
-
Homologous | bivalent
-
Homozygous | Bivalent
Question 6
Question
Crossing over occurs in ____ .
Answer
-
Prophase I
-
Metaphase I
-
Prophase II
-
Metaphase II
-
Anaphase I
-
Anaphase II
-
Telophase I
-
Telophase II
-
Cytokinesis
Question 7
Question
The four ____ cells produced in meiosis differ genetically from each other because of ____ & ____ .
Question 8
Question
Mutations occurring in the body cells of multicellular organisms are called ____ mutations.
Answer
-
Somatic
-
Nomatic
-
Domatic
-
Lomatic
-
Homatic
-
Comatic
Question 9
Question
A mutation is a change in the ____ or ____ of ____ which may result in a ____ of an organism.
Answer
-
Type | genetic structure | the cell | change in the characteristics
-
Amount | chemical structure | DNA | change in the characteristics
-
Amount | base structure | DNA | change in the functions
Question 10
Question
Non - disjunction is the term given to the ____ and go to opposite poles during the nuclear division of the nucleus.
Answer
-
Failure of a pair chromatids to separate
-
Success of a pair of chromatids separating
-
Failure of a pair of chromosomes to separate
Question 11
Question
People with down syndrome have an extra chromosome __ , giving them a total of 47 chromosomes.
Question 12
Question
In chromosome mutations there is a change in the ____ or ____ of ____ . Gene mutations are changes in the ____ of ____ in the ____ of a gene.
Question 13
Question
Sickle cell anaemia is brought about by base substitution which is an example of a gene mutation. Here ____ is substituted with ____ which causes the mutation.
Answer
-
Glu | Pro
-
Glu | His
-
Va | Glu
-
Leu | Val
-
Thr | Pro
-
Glu | Val
Question 14
Question
Haemoglobin, the ____ - transporting pigment of red cells, is made of 4 ____ molecules that interlock and form a compact molecule -two of the haemoglobin molecules are known as ____ and the other two as ____ .
Question 15
Question
The gene that codes for the amino acid sequence of beta haemoglobin occurs on chromosome ____ .
Question 16
Question
The gene that codes for beta haemoglobin is prone to a substitution of the base ____ to ____ in a codon for the amino acid glutamic acid.
Answer
-
A | T
-
T | A
-
C | A
-
A | C
-
G | C
-
C | G
-
C | T
Question 17
Question
Haemophilia is a ____ condition because the genes controlling the production of the blood proteins concerned are located on the ____ chromosome .
Answer
-
Sex - linked | X
-
Sex - linked | Y
Question 18
Question
As in mitosis, chromosomes replicate to form chromatids during interphase, however, in meiosis __ ___ chromosomes ___ and by the end of meiosis ___ they have ___ but the chromatids they consist of do not separate until meiosis __.
Answer
-
II | homologous | pair up | I | cross over | II
-
I | homologous | separate | I | separated | I
-
I | homologous | pair up | I | separated | II
-
I | homozygous | separate | II | separated | I
Question 19
Question
Ways of checking for sickle cell anaemia in embryos are:
Question 20
Question
The effects on the properties of the haemoglobin molecule if this base substitution occurs are:
Answer
-
they tend to clump together
-
they form short fibres that distort the red cells into plump disk shapes.
-
they become low in viscosity
-
they form unusually long fibres that distort the red cells into sickle shapes.
-
they become too large for the blood vessels.
Question 21
Question
The inheritance of a single characteristic is known as a monohybrid cross.
Question 22
Question
If alleles for a gene are different, they are said to be ___.
Answer
-
homozugous
-
homologous
-
heterozygous
-
heterologous
Question 23
Question
The ___ is the way in which the ___ of an organism is expressed- including the ___ of the organism.
Answer
-
genotype | phenotype
-
phenotype | genotype
-
appearance
-
beauty
Question 24
Question
when both alleles are expressed they are known as ___.
Answer
-
prodominant
-
the same
-
predominant
-
cosubmissive
-
equally powerful
-
codominant
-
this can never happen.
Question 25
Question
A gene is a pair of alleles that both affect the phenotype of an organism when present in a heterozygote.
Question 26
Question
A gene is the basic unit of inheritance by which inherited characteristics are transferred from parent to offspring, consisting of a length of DNA on a chromosome.
Question 27
Question
Examples of recessive conditions controlled by genes on the X chromosome are :
Answer
-
Haemohpilia
-
Sickle cell anaemia
-
Red-green colour blindness
-
Duchenne muscular dystrophy
-
Blue-green colour blindness