Questão 1
Questão
The largest organelle in a cell is the ____ .
Responda
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Nucleus
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Mitochondria
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Cytoplasm
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Plasma membrane
Questão 2
Questão
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.
Questão 3
Questão
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 ____ .
Responda
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Chromosome | DNA | paired | the full length | protein
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Chromosome | DNA | separate | for half | histones
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Chromatid | DNA | linked | the full length | protein
Questão 4
Questão
A pair of genes with the same alleles are called ____ .
Responda
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Homozygous
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Heterozygous
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Homologous
Questão 5
Questão
When the ____ chromosomes have paired up closely, each pair is called a ____.
Responda
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Homologous | bivalent
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Homozygous | Bivalent
Questão 6
Questão
Crossing over occurs in ____ .
Responda
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Prophase I
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Metaphase I
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Prophase II
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Metaphase II
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Anaphase I
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Anaphase II
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Telophase I
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Telophase II
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Cytokinesis
Questão 7
Questão
The four ____ cells produced in meiosis differ genetically from each other because of ____ & ____ .
Questão 8
Questão
Mutations occurring in the body cells of multicellular organisms are called ____ mutations.
Responda
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Somatic
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Nomatic
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Domatic
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Lomatic
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Homatic
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Comatic
Questão 9
Questão
A mutation is a change in the ____ or ____ of ____ which may result in a ____ of an organism.
Responda
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Type | genetic structure | the cell | change in the characteristics
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Amount | chemical structure | DNA | change in the characteristics
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Amount | base structure | DNA | change in the functions
Questão 10
Questão
Non - disjunction is the term given to the ____ and go to opposite poles during the nuclear division of the nucleus.
Responda
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Failure of a pair chromatids to separate
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Success of a pair of chromatids separating
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Failure of a pair of chromosomes to separate
Questão 11
Questão
People with down syndrome have an extra chromosome __ , giving them a total of 47 chromosomes.
Questão 12
Questão
In chromosome mutations there is a change in the ____ or ____ of ____ . Gene mutations are changes in the ____ of ____ in the ____ of a gene.
Questão 13
Questão
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.
Responda
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Glu | Pro
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Glu | His
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Va | Glu
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Leu | Val
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Thr | Pro
-
Glu | Val
Questão 14
Questão
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 ____ .
Questão 15
Questão
The gene that codes for the amino acid sequence of beta haemoglobin occurs on chromosome ____ .
Questão 16
Questão
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.
Responda
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A | T
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T | A
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C | A
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A | C
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G | C
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C | G
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C | T
Questão 17
Questão
Haemophilia is a ____ condition because the genes controlling the production of the blood proteins concerned are located on the ____ chromosome .
Responda
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Sex - linked | X
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Sex - linked | Y
Questão 18
Questão
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 __.
Responda
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II | homologous | pair up | I | cross over | II
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I | homologous | separate | I | separated | I
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I | homologous | pair up | I | separated | II
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I | homozygous | separate | II | separated | I
Questão 19
Questão
Ways of checking for sickle cell anaemia in embryos are:
Questão 20
Questão
The effects on the properties of the haemoglobin molecule if this base substitution occurs are:
Responda
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they tend to clump together
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they form short fibres that distort the red cells into plump disk shapes.
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they become low in viscosity
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they form unusually long fibres that distort the red cells into sickle shapes.
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they become too large for the blood vessels.
Questão 21
Questão
The inheritance of a single characteristic is known as a monohybrid cross.
Questão 22
Questão
If alleles for a gene are different, they are said to be ___.
Responda
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homozugous
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homologous
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heterozygous
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heterologous
Questão 23
Questão
The ___ is the way in which the ___ of an organism is expressed- including the ___ of the organism.
Responda
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genotype | phenotype
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phenotype | genotype
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appearance
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beauty
Questão 24
Questão
when both alleles are expressed they are known as ___.
Responda
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prodominant
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the same
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predominant
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cosubmissive
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equally powerful
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codominant
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this can never happen.
Questão 25
Questão
A gene is a pair of alleles that both affect the phenotype of an organism when present in a heterozygote.
Questão 26
Questão
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.
Questão 27
Questão
Examples of recessive conditions controlled by genes on the X chromosome are :
Responda
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Haemohpilia
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Sickle cell anaemia
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Red-green colour blindness
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Duchenne muscular dystrophy
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Blue-green colour blindness