To Study more of the Bio 151 Past Questions Download the Studentsdash App Now and Start Practicing.
- In chromosome karyotype, …….. represents break and join
A. 1-22
B. (+) (-)
C. :
D. ––
E. :: ✅
Explanation:
A karyotype is a representation of the number and appearance of an individual’s chromosomes. The symbol “::” is used to indicate a break and join, typically representing a structural rearrangement or translocation in chromosomes.
- 47, XX, +13 or 47, XY, +13 represents ………………..
A. Wolf-Hirschhorn syndrome
B. Down syndrome
C. Turner syndrome
D. Cri du chat syndrome
E. Patau syndrome ✅
Explanation:
Patau syndrome, also known as trisomy 13, is caused by an extra copy of chromosome 13. It occurs in about 1 in every 12,000 live births. It is associated with:
• Ambiguous genitalia
• Myelomeningocele (spina bifida)
• Holoprosencephaly (failure of the forebrain to develop)
• Abnormally formed uterus
• Microcephaly
- The region of a chromosome where the spindle fiber attaches is called
A. Telomere
B. P-arm
C. Chromatid
D. Q-arm
E. Centromere ✅
Explanation:
The centromere is a specific region on a chromosome that plays a critical role in cell division. It serves as the attachment point for spindle fibers (microtubules) during mitosis and meiosis, ensuring that chromosomes are properly separated.
- When the end of a chromosome is lost, …….. deletion occurs.
A. Terminal deletion ✅
B. Taminal deletion
C. Intastitial deletion
D. End deletion
E. Interstitial deletion
Explanation:
A terminal deletion occurs when a portion of a chromosome is lost from one of its ends. This leads to the loss of genetic material that may affect gene function.
- The ability of chromosomes to separate properly during cell division is called
A. Disjuntion
B. Disjunction ✅
C. No disjunction
D. Non-disjunction
E. Recombination
Explanation:
Disjunction is the normal separation of homologous chromosomes during meiosis or mitosis. When chromosomes fail to separate properly, it results in non-disjunction (option D), leading to conditions like Down syndrome or Turner syndrome.
- ……….. chromosome has less mass
A. Nuclear
B. Nucleic
C. Protein
D. Mitochondrial ✅
E. Spiral
Explanation:
Mitochondria are organelles found in cells that contain their own genetic material known as mitochondrial DNA (mtDNA). It is smaller and has less mass compared to nuclear DNA.
- A tetraploid organism with 5 chromosomes per set will have …….. chromosomes
A. 46
B. 20 ✅
C. 5
D. 23
E. 4
Explanation:
A tetraploid organism has four sets of chromosomes. If each set contains 5 chromosomes, then the total number of chromosomes in the cell is:
4 sets × 5 chromosomes per set = 20 chromosomes
- When a pair of chromosomes have the same traits, they are
A. Daughter chromosome
B. Homologous chromosome ✅
C. Daughter chromatid
D. Sister Chromosome
E. Sister chromatic
Explanation:
Homologous chromosomes are chromosome pairs (one from each parent) that carry the same genes, although they may have different alleles (versions of a gene).
- One of these is NOT a somatic chromosomal disorder
A. Angelman syndrome ✅
B. XYY syndrome
C. None
D. Turner syndrome
E. Klinefelter syndrome
Explanation:
Angelman syndrome is a genetic neurological disorder, not a somatic chromosomal disorder. It is caused by the deletion or inactivation of genes on chromosome 15.
- When chromatids separate, they are called
A. Duplicated chromosome
B. Offspring
C. Daughter Chromosome ✅
D. Sister Chromosome
E. Sister chromatid
Explanation:
During cell division, sister chromatids separate and become individual chromosomes, referred to as daughter chromosomes.
- Which deletion involves loss of the central chromosomal part?
A. Interstitial deletion ✅
B. Middle point deletion
C. Central deletion
D. Center deletion
E. Midpoint deletion
Explanation:
An interstitial deletion occurs when a segment of the chromosome is removed from the interior or middle portion of the chromosome.
- A chromosome where the centromere is positioned to eliminate visibility of short and long arms is called
A. Telercentric
B. Acentric
C. Metercentric
D. Metacentric
E. Telocentric ✅
Explanation:
Telocentric chromosomes have centromeres located at one end, making the short arm almost invisible.
- When the chromosome number is an exact multiple of n, …….. occurs
A. Euploidy ✅
B. Polyploidy
C. Aneuploidy
D. Trisomy
E. Monosomy
Explanation:
Euploidy is the condition where an organism has a complete set of chromosomes in a multiple of the haploid number (n).
- ………….. is one of the two copies of a chromosome
A. Chroma
B. Gene
C. Chromatid ✅
D. Allele
E. Chromosome
Explanation:
A chromatid is one of the two identical copies of a replicated chromosome that are joined together by a centromere before cell division.
- When a chromosome breaks and repairs in reverse order, …….. occurs
A. Inversion ✅
B. Chromosomal abnormality
C. Aberration
D. Reverberation
E. Translocation
Explanation:
An inversion occurs when a chromosome segment breaks off and reattaches in reverse orientation.
- The general material that collectively composes a chromosome is referred to as
A. Nucleus
B. Nuclear body
C. Chloroplast
D. Chloroplast
E. Chromatin ✅
Explanation:
Chromatin is the complex of DNA and proteins that forms chromosomes.
- A chromosome transferred only by the mother is called
A. Parental
B. Asymptotic
C. Chloroplast
D. Cell
E. Nuclear
✅ Answer: Mitochondrial DNA (not listed in options, but correct term)
Explanation:
Mitochondrial DNA (mtDNA) is inherited exclusively from the mother. This is because mitochondria in sperm are usually destroyed after fertilization.
- When a patient compulsively overeats, …………….. is suspected
A. Hypertonia
B. Morbid obesity
C. None of the above
D. Hypotonia
E. Hyperphagia ✅
Explanation:
Hyperphagia is a medical condition characterized by excessive hunger and overeating, often seen in conditions like Prader-Willi syndrome.
- …………… chromosome is seen when the centromere is at the tip
A. Metacentric
B. Telcentric
C. Metacentric
D. Acrocentric
E. Telocentric ✅
Explanation:
A telocentric chromosome has its centromere at the very end, making it look like it has only one arm.
- ……. involves the loss of two short arms and a centromere
A. None of the above
B. Interstitial Translocation
C. Robertsonian Translocation ✅
D. Translocation
E. Inversive Translocation
Explanation:
Robertsonian translocation occurs when two acrocentric chromosomes join together, losing their short arms and sharing a common centromere.
- ……………… is the functional region along the DNA molecule which constitutes the chromosome
A. Phenotype
B. Genotype
C. Allele
D. Trait
E. Gene ✅
Explanation:
A gene is the functional unit of heredity located on the DNA molecule. It codes for proteins and determines traits.
- An organism with two complete homologous sets of chromosomes is said to be
A. Human
B. Euploid
C. Eukaryotic
D. Aneuploid
E. Diploid ✅
Explanation:
Diploid organisms (2n) have two sets of chromosomes, one from each parent. Humans are diploid, with 46 chromosomes (23 pairs).
- The chromosomal constitution of any organism is called
A. Karyotype ✅
B. Phenotype
C. Caryotype
D. Nomenclature
E. Genotype
Explanation:
A karyotype is a visual representation of an organism’s chromosomes, showing their number, size, and structure.
- ………… is suspected when a chromosomal disorder requires hormones to help a woman conceive.
A. None
B. Edward’s syndrome
C. Down syndrome
D. Turner syndrome ✅
E. Patau syndrome
Explanation:
Turner syndrome (45, X) occurs in females when one X chromosome is missing. It often leads to infertility, requiring hormone therapy to conceive.
- When there is an extra set of chromosomes in a cell, ………….. occurs
A. Euploidy
B. Polyploidy ✅
C. Trisomy
D. Aneuploidy
E. Monosomy
Explanation:
Polyploidy is a condition where cells have more than two complete sets of chromosomes (e.g., triploid = 3n, tetraploid = 4n). It is common in plants but rare in humans.
- When an AB mother and a CD father produce an AC child, non-disjunction occurred on the …….. chromosome and in meiosis ……
A. None ✅
B. Father …….. two
C. Father …….. two
D. Mother ……..
E. One Father …….. one
Explanation:
This suggests that non-disjunction did NOT occur, meaning chromosome separation happened normally.
- Areas on the DNA that do not code for useful information are called
A. Non-functional region ✅
B. Coding region
C. Telomere
D. Chromatid
E. Intergenic region
Explanation:
Non-functional regions of DNA are non-coding sequences, including introns and intergenic regions. They do not produce proteins but may have regulatory functions.
- Which of these best describes genetics?
A. Study of genes, variation, and inheritance ✅
B. Study of gene’s variation and inheritance
C. Study of genes and environment
D. Study of genes and its variation
Explanation:
Genetics is the study of genes, variation, and how traits are inherited. It explains why individuals have different physical and biological characteristics.
- …………… chromosome is seen when the chromatids are not attached
A. None-centromere
B. Ascentric
C. Metacentric
D. Assentric
E. Acentric ✅
Explanation:
An acentric chromosome is a chromosome that lacks a centromere, making it unstable during cell division.
- One of these is NOT a sex chromosomal disorder
A. Klinefelter syndrome
B. Turner syndrome
C. XYY syndrome
D. Option 1 & 2
E. Angelman syndrome ✅
Explanation:
Angelman syndrome is a genetic disorder but not a sex chromosomal disorder. It is caused by deletion or mutation on chromosome 15.
- When two non-homologous chromosomes exchange pieces, ………… occurs.
A. Recombinant Inversion
B. Translocation ✅
C. Paracentric inversion
D. Reverse inversion
E. Pericentric inversion
Explanation:
Translocation occurs when segments from two different chromosomes swap places, leading to genetic disorders like chronic myeloid leukemia.
- ……………. is associated with diminished sex drive.
A. Velocardiofacial syndrome
B. Prader-Willi syndrome
C. Angelman syndrome
D. None
E. Klinefelter syndrome ✅
Explanation:
Klinefelter syndrome (47, XXY) affects males, leading to reduced testosterone levels, which causes low libido, infertility, and gynecomastia (breast enlargement).
- Humans have ………….. chromosomes.
A. 23 set, 23 pairs or 46
B. 46 set, 23 pairs or 2
C. 2 sets, 23 pairs or 46 ✅
D. None
E. 23 set, 2 pairs or 46
Explanation:
Humans are diploid organisms (2n), meaning they have two sets of chromosomes:
• 23 pairs (one from each parent)
• 46 chromosomes in total
- One of these is NOT an impact of mosaicism
A. Death
B. Loss of memory
C. Stillbirth
D. Loss of fetus ✅
E. Genetic imbalance
Explanation:
Mosaicism is when an individual has two or more genetically different cell types in their body. It can cause genetic disorders, but it does not directly lead to fetal loss.
- _ chromosomes are found in a cell of a triploid organism that has 9 chromosomes per set.
A. 9
B. 48
C. 3
D. 27 ✅
E. 23
Explanation:
A triploid organism (3n) has three sets of chromosomes. If each set contains 9 chromosomes, the total number of chromosomes is:
3 × 9 = 27 chromosomes
- One of these is an aneuploid condition
A. Cri du chat syndrome
B. Angelman Syndrome
C. Patau syndrome ✅
D. Prader-Willi syndrome
E. Turner syndrome
Explanation:
Aneuploidy refers to having an abnormal number of chromosomes. Patau syndrome (Trisomy 13) is an aneuploid condition caused by an extra chromosome 13.
- One of these is NOT a polyploid condition in humans
A. Tetraploid
B. Diploid ✅
C. Hexaploid
D. Triploid
E. Pentaploid
Explanation:
Humans are diploid (2n) by nature. Polyploidy (more than 2 sets of chromosomes) is not viable in humans but is common in plants.
- Non-disjunction commonly takes place during ……..
A. Spindle fiber attachment
B. Crossing over
C. Meiosis 2
D. Mutation
E. Meiosis 1 ✅
Explanation:
Non-disjunction happens when chromosomes fail to separate properly during cell division. It mostly occurs in Meiosis 1, leading to conditions like Down syndrome (Trisomy 21).
- The hereditary material that influences development and characteristics is called
A. Protein
B. Heredity
C. RNA
D. Gene
E. DNA ✅
Explanation:
DNA (Deoxyribonucleic Acid) contains genetic instructions that control development and characteristics in living organisms.
- ……….. occurs when one of the two X chromosomes normally found in women is missing.
A. Turner syndrome ✅
B. XYY syndrome
C. Angelman syndrome
D. Klinefelter syndrome
E. Prader-Willi syndrome
Explanation:
Turner syndrome (45, X) occurs when a female is missing one X chromosome, leading to short stature, infertility, and heart defects.
- When an AB mother and CD father produce an ABC child, non-disjunction occurred on the …….. chromosome and in meiosis ……
A. Father …… one
B. Child ……… two
C. Father ……. two
D. Mother ….. one ✅
E. Child …… One
Explanation:
Non-disjunction in meiosis 1 of the mother led to an extra chromosome being passed down to the child.
- ……… chromosomes are mostly circular.
A. Nuclear
B. Some
C. Every
D. Cell
E. Cytoplasmic ✅
Explanation:
Cytoplasmic chromosomes (such as mitochondrial DNA in animals and chloroplast DNA in plants) are circular in structure, unlike linear nuclear chromosomes.
- ……………… is the condition with missing or additional chromosomes.
A. Polyploidy
B. Trisomy
C. Monosomy
D. Euploidy
E. Aneuploidy ✅
Explanation:
Aneuploidy is when an organism has an abnormal number of chromosomes (e.g., Trisomy 21 in Down syndrome or Monosomy X in Turner syndrome).
- When the spinal cord protrudes through an opening in the spinal column, …….. occurs
A. Autism
B. Myelomeningocele ✅
C. Hypogonadism
D. Hypergonadism
E. Holoprosencephaly
Explanation:
Myelomeningocele, a form of spina bifida, happens when the spinal cord and its protective covering bulge out through a defect in the spinal bones.