Molecular Biology Quizzes for Sixth Form College Year 12 Biology Students

Question 1

In animal cells, which statement accurately describes the relationship between mitosis and cytokinesis?

Accepted Answer

Mitosis is nuclear division, resulting in two daughter cells with identical chromosomes. Cytokinesis physically separates these daughter cells.

Answer

Cytokinesis in animal cells involves forming a cell wall to separate daughter cells.

Answer

Mitosis and cytokinesis occur simultaneously in animal cells.

Answer

During mitosis in animal cells, chromosomes align randomly at the metaphase plate.

Question 2

Which of the following is NOT a stage of mitosis? Provide a brief explanation for your answer.

Accepted Answer

Interphase

Answer

Prophase

Answer

Metaphase

Answer

Anaphase

Question 3

Which process is unique to meiosis, and not involved in mitosis?

Accepted Answer

Homologous chromosome pairing

Answer

Chromosome condensation

Answer

Nuclear envelope breakdown

Answer

Formation of a metaphase plate

Question 4

Which of these factors does NOT influence the rate of photosynthesis?

Accepted Answer

Distance from the equator

Answer

Temperature

Answer

Light availability

Answer

Concentration of chlorophyll

Question 5

Which of the following is NOT a stage in the cell cycle?

Accepted Answer

Senescence

Answer

Interphase

Answer

Prophase

Answer

Metaphase

Question 6

Which cell division process produces genetically identical daughter cells?

Accepted Answer

Mitosis

Answer

Meiosis

Answer

Binary Fission

Answer

DNA Replication

Question 7

In pea plants, the allele for tall stems (T) is dominant over the allele for short stems (t). If a heterozygous plant (Tt) is crossed with a homozygous recessive plant (tt), what percentage of the offspring will have short stems?

Accepted Answer

25%

Answer

0%

Answer

50%

Answer

75%

Question 8

In the cell cycle, which phase is dedicated to duplicating the genetic material?

Accepted Answer

S phase

Answer

Interphase

Answer

Prophase

Answer

Metaphase

Question 9

In meiosis, how does crossing-over contribute to genetic variation?

Accepted Answer

It creates new allele combinations, increasing diversity.

Answer

It ensures random allele distribution in gametes.

Answer

It eliminates harmful alleles, reducing genetic disorders.

Answer

It promotes homozygosity, increasing genetic stability.

Question 10

What is the key difference between mitosis and meiosis in terms of the number and genetic makeup of the resulting daughter cells?

Accepted Answer

Mitosis produces two genetically identical daughter cells, while meiosis results in four haploid daughter cells.

Answer

Meiosis occurs in reproductive cells, while mitosis takes place in somatic cells.

Answer

Mitosis involves the separation of sister chromatids, while meiosis entails the separation of homologous chromosomes.

Answer

Mitosis results in genetically diverse daughter cells, unlike meiosis, which yields genetically identical daughter cells.

Question 11

Which of the following is used to predict the likelihood of offspring inheriting specific traits but is not a type of genetic cross?

Accepted Answer

Punnett square

Answer

Monohybrid cross

Answer

Dihybrid cross

Answer

Backcross

Question 12

Genetic drift can disrupt Hardy-Weinberg equilibrium. What is the reason for this?

Accepted Answer

Genetic drift causes random changes in allele frequencies, potentially leading to allele loss.

Answer

Genetic drift accelerates natural selection, resulting in the fixation of alleles.

Answer

Genetic drift increases mutation accumulation, disrupting gene flow.

Answer

Genetic drift promotes gene flow between populations, introducing new alleles.

Question 13

In mitosis, which sequence correctly represents the stages of the process?

Accepted Answer

Prometaphase, Metaphase, Anaphase, Telophase

Answer

Prometaphase, Metaphase, Telophase, Anaphase

Answer

Metaphase, Prometaphase, Anaphase, Telophase

Answer

Telophase, Metaphase, Anaphase, Prometaphase

Question 14

Which phase of meiosis follows both Prophase I and Prophase II?

Accepted Answer

Interkinesis

Answer

Metaphase I

Answer

Anaphase II

Answer

Telophase II

Question 15

Which cell division process produces haploid gametes?

Accepted Answer

Meiosis

Answer

Mitosis

Answer

Binary fission

Answer

Budding

Question 16

Which sequence correctly represents the phases of mitosis?

Accepted Answer

Prophase, Metaphase, Anaphase, Telophase

Answer

Interphase, Prophase, Metaphase, Anaphase

Answer

Anaphase, Metaphase, Prophase, Telophase

Answer

Telophase, Prophase, Anaphase, Metaphase

Question 17

Which phase of the cell cycle is not directly involved in mitosis?

Accepted Answer

Interphase

Answer

Prophase

Answer

Metaphase

Answer

Anaphase

Question 18

Which of the following is not a stage of the cell cycle?

Accepted Answer

Metastasis

Answer

Interphase

Answer

Prophase

Answer

Telophase

Question 19

What are the main characteristics of meiosis?

Accepted Answer

Meiosis produces four haploid daughter cells through two rounds of division and involves crossing over between homologous chromosomes.

Answer

Meiosis only occurs in male gametes and produces two diploid daughter cells.

Answer

Meiosis is a continuous process that doesn't involve the exchange of genetic material between chromosomes.

Answer

Meiosis produces diploid daughter cells with half the genetic material of the parent cell.

Question 20

During meiosis, how do homologous chromosomes differ in behavior compared to mitosis?

Accepted Answer

Homologous chromosomes pair and exchange genetic material.

Answer

Homologous chromosomes are randomly distributed to daughter cells.

Answer

The number of chromosomes in a cell remains constant.

Answer

Homologous chromosomes are present in both body cells and gametes.

Question 21

Which disorder is caused by an additional copy of chromosome 21?

Accepted Answer

Down's syndrome

Answer

Turner's syndrome

Answer

Klinefelter's syndrome

Answer

Sickle cell anemia

Question 22

During the mitotic cell cycle, in which phase do the sister chromatids of each chromosome align along the metaphase plate?

Accepted Answer

Metaphase

Answer

Prophase

Answer

Anaphase

Answer

Telophase

Question 23

Pedigree diagrams are valuable tools for studying the inheritance of genetic traits in families. What information can pedigree diagrams provide about the inheritance of dominant and recessive alleles?

Accepted Answer

The inheritance of both dominant and recessive alleles

Answer

The inheritance of only recessive alleles

Answer

The inheritance of dominant alleles only

Question 24

In a dihybrid cross involving two independent traits, what is the probability of getting offspring with both recessive traits?

Accepted Answer

1/16

Answer

1/4

Answer

1/8

Answer

1/32

Question 25

In which phase of the cell cycle does DNA replication take place?

Accepted Answer

S phase

Answer

Prophase

Answer

Metaphase

Answer

Telophase

Question 26

Which feature is unique to prokaryotic cells?

Accepted Answer

Cell wall made of peptidoglycan

Answer

Membrane-bound nucleus

Answer

Mitochondria

Answer

Ribosomes

Question 27

In Mendelian inheritance, which principle describes the separation of alleles during gamete formation?

Accepted Answer

Each gamete carries only one allele for a specific gene, ensuring that alleles separate during gamete formation.

Answer

Mendel's principles only apply to monohybrid crosses.

Question 28

During which cell division process does the exchange of genetic material between homologous chromosomes occur?

Accepted Answer

Meiosis I

Answer

Mitosis

Answer

Meiosis II

Question 29

At which stage of the cell cycle do chromosomes become visible?

Accepted Answer

Prophase

Answer

Interphase

Answer

Anaphase

Question 30

Explain the crucial role of ATP in cellular respiration and describe the mechanism by which it is generated.

Accepted Answer

ATP serves as the energy currency of the cell, providing the necessary energy for various cellular processes.

Accepted Answer

ATP is generated primarily within the mitochondria, utilizing the energy released during the electron transport chain.

Answer

ATP is produced solely through the breakdown of glucose in the cytoplasm.

Answer

ATP is a by-product of cellular respiration that is removed from the cell.

Question 31

When a heterozygous individual with one dominant and one recessive allele is crossed with a homozygous recessive individual, what inheritance pattern is most likely to be observed?

Accepted Answer

Half of the offspring will inherit the dominant allele, and half will inherit the recessive allele.

Answer

All offspring will show the dominant phenotype.

Answer

All offspring will show the recessive phenotype.

Question 32

According to Mendel's law of segregation, what happens to alleles of a gene during gamete formation?

Accepted Answer

They separate into different gametes

Answer

They stay together in the same gamete

Answer

They are randomly distributed among all gametes

Question 33

Which of the following is NOT a mechanism by which bacteria develop resistance to antibiotics?

Accepted Answer

Increased cell wall permeability

Answer

Efflux pumps

Answer

Enzymatic degradation

Answer

Altered antibiotic targets

Question 34

During mitosis, which phase involves the separation and movement of sister chromatids to opposite ends of the cell?

Accepted Answer

Anaphase

Answer

Prophase

Answer

Metaphase

Answer

Telophase

Question 35

Which enzyme initiates DNA replication by unwinding the original DNA strands?

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

Ligase

Answer

Primase

Question 36

During DNA replication, what are the specific roles of DNA helicase, DNA polymerase, and RNA primase?

Accepted Answer

DNA helicase unwinds the double helix, DNA polymerase synthesizes new strands, and RNA primase synthesizes short RNA primers.

Answer

DNA helicase synthesizes new strands, DNA polymerase unwinds the double helix, and RNA primase removes RNA primers.

Answer

RNA primase unwinds the double helix, DNA polymerase synthesizes new strands, and DNA helicase removes RNA primers.

Question 37

In Mendelian monohybrid crosses, the relationship between the gene and the polypeptide it produces is:

Accepted Answer

The gene encodes the polypeptide

Answer

The polypeptide is a copy of the gene

Answer

The gene is a segment of the polypeptide

Answer

The polypeptide is a modified form of the gene

Question 38

Which type of RNA carries the genetic information from DNA to the ribosomes?

Accepted Answer

mRNA

Answer

rRNA

Answer

tRNA

Answer

snRNA

Question 39

The process by which a DNA molecule is duplicated into two identical copies is called:

Accepted Answer

Replication

Answer

Transcription

Answer

Translation

Answer

Mutation

Question 40

Which of the following amino acids is encoded by the codon UUU?

Accepted Answer

Phenylalanine

Answer

Alanine

Answer

Serine

Answer

Tyrosine

Question 41

The three-dimensional shape of a protein is primarily determined by its:

Accepted Answer

Tertiary structure

Answer

Primary structure

Answer

Secondary structure

Answer

Quaternary structure

Question 42

Which of the following techniques is commonly used to separate DNA fragments based on their size?

Accepted Answer

Gel electrophoresis

Answer

PCR

Answer

DNA sequencing

Answer

Southern blotting

Question 43

The enzyme responsible for separating the DNA strands during replication is:

Accepted Answer

Helicase

Answer

Polymerase

Answer

Primase

Answer

Ligase

Question 44

Which of the following regions of DNA is non-coding?

Accepted Answer

Intron

Answer

Promoter

Answer

Exon

Answer

Terminator

Question 45

A mutation that results in the insertion of an additional base pair into a gene is called:

Accepted Answer

Insertion

Answer

Deletion

Answer

Substitution

Answer

Translocation

Question 46

Which of the following techniques is used to study the expression of genes in a cell?

Accepted Answer

Microarray

Answer

Bioinformatics

Answer

Proteomics

Answer

Genome editing

Question 47

What is the fundamental principle of information flow in biological systems, according to the central dogma of molecular biology?

Accepted Answer

DNA → RNA → Proteins

Answer

DNA → Proteins → RNA

Answer

Proteins → RNA → DNA

Answer

RNA → Proteins → DNA

Question 48

Which of the following amino acids is hydrophobic?

Accepted Answer

Alanine

Answer

Serine

Answer

Glutamic acid

Answer

Histidine

Question 49

What level of protein structure represents the linear sequence of amino acids?

Accepted Answer

Primary structure

Answer

Secondary structure

Answer

Tertiary structure

Answer

Quaternary structure

Question 50

Which technique is commonly used to separate DNA fragments by size?

Accepted Answer

Gel electrophoresis

Answer

Chromatography

Answer

Centrifugation

Answer

Spectrophotometry

Question 51

What is the primary function of enzymes in biological reactions?

Accepted Answer

Speed up reactions

Answer

Provide energy for reactions

Answer

Change the equilibrium of reactions

Answer

Alter the products of reactions

Question 52

What is the main significance of DNA replication?

Accepted Answer

Ensures accurate transmission of genetic information

Answer

Provides energy for cellular processes

Answer

Regulates gene expression

Answer

Repairs damaged DNA

Question 53

Which of the following is not a characteristic of DNA?

Accepted Answer

Carries nutrients through the bloodstream

Answer

Double-stranded structure

Answer

Contains genetic information

Answer

Can replicate itself

Question 54

Which of the following is a nitrogenous base present in DNA?

Accepted Answer

Adenine

Answer

Glucose

Answer

Ribose

Answer

Uracil

Question 55

What is the function of messenger RNA (mRNA) in protein synthesis?

Accepted Answer

Carries genetic information from DNA to the ribosome

Answer

Serves as a template for protein synthesis

Answer

Provides the amino acids for protein assembly

Answer

Enzymes that catalyze protein synthesis

Question 56

What is the primary structure of a protein?

Accepted Answer

Sequence of amino acids

Answer

Folding of the protein chain

Answer

Three-dimensional shape

Answer

Functional site of the protein

Question 57

What is the role of enzymes in biological reactions?

Accepted Answer

Speed up reactions without being consumed

Answer

Provide the energy for reactions

Answer

React with the substrate to form a new product

Answer

Alter the equilibrium of reactions

Question 58

Which of the following is an example of a competitive enzyme inhibitor?

Accepted Answer

Substrate analogue

Answer

Metal ion chelator

Answer

Feedback inhibitor

Answer

Allosteric modulator

Question 59

Which enzyme is responsible for adding nucleotides to the growing DNA strand during DNA replication?

Accepted Answer

DNA Polymerase

Answer

Helicase

Answer

Ligase

Answer

Primase

Question 60

Which nitrogenous base is found exclusively in RNA and not in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Answer

Guanine

Question 61

Why is the genetic code nearly universal across all living organisms?

Accepted Answer

It allows all organisms to decode DNA and RNA using the same genetic code.

Answer

It enables the evolution of new genetic codes in response to environmental changes.

Answer

It prevents the accumulation of harmful mutations in the genome.

Answer

It enables the direct transfer of genetic material between organisms of different species.

Question 62

Explain how DNA repair mechanisms maintain genomic stability and prevent cancer and genetic disorders.

Accepted Answer

DNA repair mechanisms constantly monitor and correct DNA damage, ensuring genomic stability.

Accepted Answer

DNA repair pathways play a vital role in preventing genetic disorders by correcting mutations that could cause developmental abnormalities.

Answer

Defective DNA repair pathways are solely responsible for cancer development.

Question 63

Which of the following describes the key difference between prokaryotic and eukaryotic DNA replication initiation?

Accepted Answer

Prokaryotic cells have a single replication origin, while eukaryotic cells have multiple replication origins.

Answer

Eukaryotic cells have double-stranded DNA, while prokaryotic cells have single-stranded DNA.

Answer

Prokaryotic cells use DNA polymerase, while eukaryotic cells use RNA polymerase.

Answer

Eukaryotic cells have histones, while prokaryotic cells have no histones.

Question 64

Which of the following is NOT a major milestone in the historical development of molecular biology techniques?

Accepted Answer

The development of gene editing techniques, such as CRISPR-Cas9

Answer

The discovery of the structure of DNA

Answer

The development of DNA sequencing techniques

Answer

The invention of the polymerase chain reaction (PCR)