Q.1 Who is considered the father of modern genetics?
Charles Darwin
Gregor Mendel
Watson and Crick
Thomas Hunt Morgan
Explanation - Gregor Mendel discovered the basic principles of heredity through experiments with pea plants, laying the foundation of modern genetics.
Correct answer is: Gregor Mendel
Q.2 Which type of genetic inheritance involves a trait expressed only when two recessive alleles are present?
Dominant
Recessive
Codominant
Incomplete dominance
Explanation - A recessive trait is expressed phenotypically only when both alleles are recessive.
Correct answer is: Recessive
Q.3 What is the chromosomal pattern in a normal human male?
XX
XY
XO
YY
Explanation - Males have one X and one Y chromosome, while females have two X chromosomes.
Correct answer is: XY
Q.4 Down syndrome is caused by which chromosomal abnormality?
Trisomy 21
Monosomy X
Trisomy 18
Deletion of chromosome 5
Explanation - Down syndrome results from an extra copy of chromosome 21, leading to trisomy 21.
Correct answer is: Trisomy 21
Q.5 Which molecule carries genetic information in humans?
RNA
DNA
Protein
Lipid
Explanation - DNA (deoxyribonucleic acid) carries hereditary information in the form of genes.
Correct answer is: DNA
Q.6 What is the probability of having a child with cystic fibrosis if both parents are carriers?
25%
50%
75%
100%
Explanation - Cystic fibrosis is an autosomal recessive disorder; if both parents are carriers, each child has a 25% chance of being affected.
Correct answer is: 25%
Q.7 Which part of the chromosome is critical for proper segregation during cell division?
Telomere
Centromere
Chromatid
Nucleosome
Explanation - The centromere is the region where sister chromatids are held together and where spindle fibers attach during cell division.
Correct answer is: Centromere
Q.8 Which of the following is an example of a sex-linked disorder?
Color blindness
Cystic fibrosis
Sickle cell anemia
Phenylketonuria
Explanation - Color blindness is commonly X-linked, mostly affecting males, because they have only one X chromosome.
Correct answer is: Color blindness
Q.9 Karyotyping is primarily used to:
Sequence DNA
Visualize chromosomes
Detect proteins
Measure gene expression
Explanation - Karyotyping involves staining and visualizing chromosomes to detect numerical and structural abnormalities.
Correct answer is: Visualize chromosomes
Q.10 Mitochondrial DNA is inherited from which parent?
Father
Mother
Both parents
Depends on the trait
Explanation - Mitochondrial DNA is passed down maternally, as sperm mitochondria are typically not transmitted to the embryo.
Correct answer is: Mother
Q.11 Which genetic disorder is associated with an extra X chromosome in males?
Turner syndrome
Klinefelter syndrome
Down syndrome
Edward syndrome
Explanation - Klinefelter syndrome occurs in males with the karyotype 47,XXY, resulting in physical and reproductive abnormalities.
Correct answer is: Klinefelter syndrome
Q.12 Which enzyme is responsible for DNA replication?
DNA polymerase
RNA polymerase
Ligase
Helicase
Explanation - DNA polymerase synthesizes new DNA strands complementary to the template strand during replication.
Correct answer is: DNA polymerase
Q.13 Sickle cell anemia results from a mutation in which gene?
HBB
CFTR
BRCA1
FMR1
Explanation - Sickle cell anemia is caused by a point mutation in the beta-globin gene (HBB), altering hemoglobin structure.
Correct answer is: HBB
Q.14 Which of the following is an example of a multifactorial trait?
Eye color
Height
Blood type
Huntington disease
Explanation - Height is influenced by multiple genes and environmental factors, making it a multifactorial trait.
Correct answer is: Height
Q.15 Which term describes the physical expression of a gene?
Genotype
Phenotype
Allele
Chromosome
Explanation - Phenotype refers to the observable traits resulting from the interaction of genotype and environment.
Correct answer is: Phenotype
Q.16 Huntington disease is inherited in which pattern?
Autosomal dominant
Autosomal recessive
X-linked dominant
X-linked recessive
Explanation - Huntington disease is an autosomal dominant disorder, meaning a single copy of the mutant allele can cause the disease.
Correct answer is: Autosomal dominant
Q.17 Which of the following techniques can be used for prenatal diagnosis of genetic disorders?
Amniocentesis
Western blot
ELISA
MRI
Explanation - Amniocentesis allows sampling of amniotic fluid to test fetal cells for chromosomal or genetic abnormalities.
Correct answer is: Amniocentesis
Q.18 Which blood type is considered the universal donor?
A
B
AB
O
Explanation - Blood type O lacks A and B antigens, making it compatible with recipients of any ABO blood type.
Correct answer is: O
Q.19 Which chromosomal abnormality causes Turner syndrome?
45,X
47,XXY
Trisomy 21
Trisomy 18
Explanation - Turner syndrome occurs in females with only one X chromosome (45,X), leading to short stature and infertility.
Correct answer is: 45,X
Q.20 Which type of RNA carries amino acids to the ribosome during protein synthesis?
mRNA
tRNA
rRNA
snRNA
Explanation - tRNA (transfer RNA) transports specific amino acids to the ribosome and matches them to the mRNA codon.
Correct answer is: tRNA
Q.21 Which term refers to the study of the inheritance of human traits and diseases?
Cytology
Genetics
Human genetics
Molecular biology
Explanation - Human genetics focuses on understanding the inheritance, variation, and genetic disorders in humans.
Correct answer is: Human genetics
Q.22 Which process produces gametes in humans?
Mitosis
Meiosis
Fertilization
Binary fission
Explanation - Meiosis reduces the chromosome number by half, producing haploid gametes (sperm and egg) for sexual reproduction.
Correct answer is: Meiosis
Q.23 Which is a common cause of chromosomal disorders in humans?
Point mutation
Nondisjunction
Transcription error
Translation error
Explanation - Nondisjunction is the failure of chromosomes to separate properly during meiosis, causing aneuploidies like Down syndrome.
Correct answer is: Nondisjunction
Q.24 Which type of mutation involves the substitution of a single nucleotide?
Frameshift
Point mutation
Deletion
Insertion
Explanation - A point mutation is a change in a single nucleotide, which can alter protein function or be silent.
Correct answer is: Point mutation
Q.25 Which technology allows direct modification of specific DNA sequences in humans?
CRISPR-Cas9
PCR
Gel electrophoresis
Karyotyping
Explanation - CRISPR-Cas9 is a genome editing tool that can precisely alter DNA sequences in living organisms, including humans.
Correct answer is: CRISPR-Cas9