Tag: zoology

Questions Related to zoology

Pili, Fimbriae and flagella

zoology locomotion and reproduction flagella other cell components single membrane bound organelles

  1. Play a role in motility in bacteria

  2. Are surface structures of bacteria

  3. Play a role in motility in eukaryotic cells

  4. Are elongated tubular structures made of a special phospholipid

Show answer
Correct Option: B
Explanation:

Pili, Fimbriae and flagella are structures that are found on the cell wall of the bacteria. These are structures that are made out of cellular components like proteins, for example, Pilli is made up of the protein pilin and flagella is made up of the protein flagellin.

Flagella are longer than both pili and fimbriae. These are a surface structure of the bacteria.
So, the correct option is 'Are surface structures of bacteria'

Arrangement of microtubules in a flagellum and a centriole is _______ and ________ respectively.

zoology locomotion and reproduction flagella other cell components single membrane bound organelles

  1. $9 + 2$ and $9 + 1$

  2. $9 + 1$ and $9 + 0$

  3. $9 + 0$ and $9 + 2$

  4. $9 + 2$ and $9 + 0$

Show answer
Correct Option: D
Explanation:
A centriole possesses a whorl of nine peripheral fibrils. Fibrils are absent in the centre. The arrangement is, therefore, called $9 + 0$. Flagellum contains an axoneme of a peripheral doublet fibrils and $2$ central singlet fibrils. This arrangement is called $9 + 2$ or $11$ stranded.
So, the correct answer is '9+2 and 9+0'.

Filaments present in flagella/cilia are

zoology locomotion and reproduction flagella other cell components single membrane bound organelles

  1. Microfibrils

  2. Microtubules

  3. Microfilaments

  4. Microvilli

Show answer
Correct Option: B
Explanation:
  • Cilia and flagella are small hair-like projections from the cell and are composed of microtubules which are arranged with their positive end at the outer tip of the axoneme.
  • A microtubule is a tubular linear polymer of tubulin protein which is a part of the cytoskeleton that helps to provide structure and shape to the cytoplasm of a eukaryotic cell.
  • So, the correct answer is 'Microtubules'.

The variation in pattern of 9+2 in cilium or flagellum is shown by 

zoology locomotion and reproduction flagella other cell components single membrane bound organelles

  1. Flatworm

  2. Eel

  3. Sporozoan protozoan

  4. All of the above

Show answer
Correct Option: D
Explanation:

The 9+2 arrangement of fibrils is characteristics of eukaryotes being comprised of 9 peripheral doublet and 2 central singlet fibrils. Although the 9 + 2 pattern is the fundamental pattern of virtually all cilia and flagella, the axonemes of certain sporozoan protozoans and some insect sperm show some interesting variations. The spermatozoids of flatworms are also atypical. The eel sperm shows 9+0 arrangement. These atypical cilia and flagella, which are all motile, show that the central pair of singlet microtubules is not necessary for axonemal beating and that fewer than nine outer doublets can sustain motility, but at a lower frequency.

Which of the following statement regarding cilia is not correct?

zoology locomotion and reproduction flagella other cell components single membrane bound organelles

  1. Cilia contain an outer ring of nine doublet microtubles surrounding two single microtubles.

  2. Cilia is an organelle found in prokaryotes.

  3. Cilia are short, hair-like cellular appendages.

  4. Microtubules of cilia are composed of tubulin.

Show answer
Correct Option: B
Explanation:

Cilia are short, hair like appendages extending from the surface a living cell. Cilia are found exclusively in the prokaryotes.

Which out of the following statements is incorrect?

zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

  1. Genetic code is ambiguous.

  2. Genetic code is degenerate.

  3. Genetic code is universal.

  4. Genetic code is non-overlapping.

Show answer
Correct Option: A
Explanation:

Since there are 64 triplet codons and only 20 amino acids, genetic code is non-ambiguous. Non-ambiguous code means that there is no ambiguity about a particular code. One codon specifies only one amino acid and not any other except GUG which normally codes for valine but in certain conditions it also codes for N-formyl methionine as initiation codon.

Choose the correct answer from the alternatives given, Human genome consists of approximately

zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

  1. $3 \, \times \, 10^9$ bp

  2. $6 \, \times \, 10^9$ bp

  3. 20,000 + 25,000 bp

  4. $2.2 \, \times \, 10^4$ bp

Show answer
Correct Option: A
Explanation:
The human genome contains 23 chromosomes. The DNA in the haploid set contains 3 billion base pairs.
So, the correct answer is '($3\, \times \,10^9$ bp)'

Choose the correct answer from the alternatives given :
Which of the following statements regarding human genome is incorrect?

zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

  1. Human genome consists of $3 \, \times \, 10^9$ bp and about 20,500 genes.

  2. The average gene size is 3000 bop and dystrophin is the largest known human gene.

  3. Chromosome 1 contains maximum (2968) number of genes and Y-chrbmosome has the least (231) number of genes.

  4. Repeated (or repetitive) sequences are not present in human genome.

Show answer
Correct Option: D
Explanation:

Repeated or repetitive sequences make up large portion of human genome. Repetitive sequences are nucleotide sequences that are repeated many times, sometimes hundred to thousand times. They have no direct coding function but provide information as to chromosome structure, dynamics and evolution. Approximately 1 million copies of short 5-8 base pair repeated sequences are clustered around centromeres and near the ends of chromosomes. They represent junk DNA. 

So, the correct answer is 'Repeated (or repetitive) sequences are not present in human genome'.

All living organism present past and future are 

zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

  1. Not linked to any extent

  2. Linked to one another in their cell membrane

  3. Linked to one another by the sharing of the common genetic materials ,but to varying degrees

  4. Linked to another by the sharing of the common genetic material to $100\%$ extent

Show answer
Correct Option: C
Explanation:

All living organisms—present, past and future are linked to one another by the sharing of the common genetic material, but to varying degrees.

The genetic material of living organisms undergoes mutations and reshuffling of genes. This causes variations in the genetic material. Variations are so abundant that no two individuals of the same race are exactly similar.
So the answer is 'Linked to one another by the sharing of the common genetic materials, but to varying degrees'. 

Which of the following is an application  of human genome project?

zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

  1. Understanding of phylogenetic disorder

  2. Improvement in gene therapy

  3. Understanding of mutation concept

  4. All of the above

Show answer
Correct Option: D