Biology for IGCSE & O level - Inheritance (Section 4)
1
If a recessive allele is present in a population, but does not express itself, what must be true about the individual?
Answer
(A)
The individual is heterozygous.
2
What type of allele is expressed only in the absence of a dominant allele?
Answer
(B)
Recessive allele
3
What is the probability of producing an offspring with the genotype Aa from a cross between two parents who are both Aa?
Answer
(C)
50%
4
What is the role of the centromere?
Answer
(C)
To connect sister chromatids.
5
Which of the following are true regarding the process of transcription?
Answer
A
B
6
In a pedigree chart, what does a circle represent?
Answer
(B)
A female individual
7
Which processes contribute to genetic variation in sexually reproducing organisms?
Answer
A
B
D
8
How many chromosomes are present in a human egg cell?
Answer
(A)
23
9
What is the purpose of a test cross?
Answer
(A)
To determine if an individual is homozygous dominant or heterozygous for a trait.
10
Which statement accurately describes the concept of sex-linked traits?
Answer
(C)
Traits determined by genes located on the sex chromosomes.
11
In a monohybrid cross, what is the expected phenotypic ratio in the F2 generation when both parents are heterozygous for a single trait (assuming complete dominance)?
Answer
(A)
3:1
12
What are the main products of protein synthesis?
Answer
(B)
Proteins
13
Which of the following genetic conditions is most likely to affect males more frequently than females?
Answer
(C)
X-linked recessive conditions
14
What is the primary difference between mitosis and meiosis?
Answer
(B)
Mitosis produces genetically identical cells, while meiosis produces genetically diverse cells.
15
What would be the probable outcome of a cross involving unlinked genes that are independently assorting?
Answer
(C)
The genes will show a 9:3:3:1 phenotypic ratio
16
Which of the following factors contribute to the overall phenotype of an organism?
Answer
A
B
D
17
Which of the following are the phases of mitosis?
Answer
A
B
C
D
18
Which of the following genetic events leads to new combinations of alleles?
Answer
A
B
C
19
Which of the following are potential results of a mutation?
Answer
A
B
C
D
20
What are the building blocks of proteins?
Answer
(B)
Amino acids
21
Which of the following is/are the main functions of meiosis?
Answer
A
B
C
22
Which of the following best describes the function of a gene?
Answer
(C)
To code for the production of a specific protein.
23
Which of the following are involved in protein synthesis?
Answer
A
B
C
24
What is the central dogma of molecular biology?
Answer
(C)
DNA -> RNA -> Protein
25
What is the name of the process where homologous chromosomes exchange genetic information?
Answer
(D)
Crossing over
26
Which of the following best describes the Law of Segregation?
Answer
(A)
Alleles for the same trait separate during gamete formation.
27
Which process occurs during both mitosis and meiosis?
Answer
(B)
Replication of chromosomes
28
What is the purpose of the synapsis during prophase I of meiosis?
Answer
(C)
To allow homologous chromosomes to pair up.
29
What does the term 'carrier' mean in the context of human genetics?
Answer
(C)
Someone who is heterozygous for a recessive allele.
30
What is the function of a promoter region?
Answer
(C)
To signal the start of transcription.
31
What roles does DNA play in cells?
Answer
A
B
C
32
Which of the following is a potential source of variation in offspring?
Answer
A
B
D
33
What is the term for the observable characteristics of an organism?
Answer
(B)
Phenotype
34
Which of the following statements about DNA structure is/are correct?
Answer
B
D
35
What is the primary function of ribosomes in a cell?
Answer
(B)
Protein synthesis
36
Which of the following is an example of incomplete dominance?
Answer
(B)
Flower color in snapdragons
37
What blood type(s) can a person with blood type AB receive blood from?
Answer
(C)
A, B, AB, and O
38
Which of the following genotypes would represent a homozygous dominant individual?
Answer
(C)
AA
39
Which of the following is NOT directly involved in the process of translation?
Answer
(D)
DNA
40
Which of the following is true regarding the number of chromosomes in gametes?
Answer
(C)
Gametes have half the number of chromosomes as somatic cells.
41
In what phase of meiosis does crossing over occur?
Answer
(A)
Prophase I
42
Which of the following is an example of a trait that follows Mendelian inheritance?
Answer
(C)
Pea seed shape
43
Which of the following are true regarding X-linked traits?
Answer
A
B
44
What type of cell division is involved in the growth and repair of an organism?
Answer
(C)
Mitosis
45
What is the result of mitosis?
Answer
(A)
Two genetically identical cells
46
Which of the following is the location where translation takes place?
Answer
(B)
Ribosome
47
During which phase of meiosis does the nuclear envelope and nucleolus disappear?
Answer
(A)
Prophase I
48
Which of the following events occurs during Anaphase I of meiosis?
Answer
(A)
Homologous chromosomes separate.
49
Which of the following events occurs during anaphase II of meiosis?
Answer
(B)
Sister chromatids separate.
50
What is the role of the Y chromosome in sex determination in humans?
