Biology · Science General

Cell Biology and Structure

3,221 Questions

Cell biology focuses on the structure and function of cellular organelles. Key topics include cellular respiration, DNA inheritance, and energy production. These fundamental biology concepts are crucial for medical entrance and state service examinations.

Cell organelles functionsCellular respiration sitesDNA and ribosomesAnimal cell structurePlant cell components

Cell Biology and Structure Questions

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Epinephrine and eicosanoids finds their receptors on

  1. Cell wall

  2. Plasma membrane

  3. Inner matrix

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  •  Eicosanoids are compounds that include prostaglandins, prostacyclins, leukotrienes, and thromboxanes.
  • Lipid insoluble hormones such as eicosanoids bind to receptors on the outer surface of the plasma membrane, via plasma membrane hormone receptors.
  • The amino acid-derived hormones epinephrine and norepinephrine bind to beta-adrenergic receptors on the plasma membrane of cells.
  • Hence the Epinephrine and eicosanoids find their receptors on the plasma membrane.
  • So, the correct answer is 'Plasma membrane'.
Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which of the following is not involved as $2^{nd}$ messenger?

  1. cAMP

  2. DAG

  3. Phospholipase
  4. $IP _{3}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

cAMP, DAG, and IP3 are well-known second messengers. Phospholipase C is an enzyme that generates second messengers (like DAG and IP3), but it is not a second messenger itself.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Signalling between cells usually results in activation of protein by

  1. Kinases

  2. Proteases

  3. Lipases

  4. Nucleases
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Signalling is the communication between cells by means of signalling molecules. When a ligand binds to its receptor, ligand-receptor complex is formed which activate protein kinases. Kinases are the enzymes that transfer phosphate group to the target cells. Phosphorylation of target cells cause different changes in the cell.
So, the correct answer is 'Kinases'.
Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Negative feedback occurs when

  1. The rate of a process increases as the concentration of product increases.

  2. The rate of process decreases as the concentration of product decreases.

  3. The rate of process decreases as the concentration of product increases.

  4. The rate of a process increases as the concentration of product decreases.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • A feedback mechanism for multistep reactions is a biological occurrence wherein the output of a system amplifies the system (positive feedback) or inhibits the system (negative feedback).
  • For example, Release of estrogen from the ovaries stimulates the secretion of GnRH from Hypothalamus which in turn stimulates the secretion of LH from anterior pituitary.when the levels of LH reaches above the normal levels in the blood it stimulates the release of progesterone from corpus luteum which causes the inhibition of the release of GnRH from the hypothalamus which in turn leads to inhibition of release of LH(product) from anterior pituitary and prevents the accumulation of LH(product)in blood. Hence negative feedback.
  • Hence Negative feedback occurs when The rate of process decreases as the concentration of product increases.
  • So, the correct answer is 'The rate of process decreases as the concentration of product increases'.
Multiple choice botany tissue culture common modes of vegetative propagation plant breeding for food production plant tissue culture

The term 'totipotency' refers to the capacity of a 

  1. cell to generate whole plant

  2. bud to generate whole plant

  3. seed to germinate

  4. cell to enlarge in size
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The capacity to generate a whole new plant from any cell is called totipotency. That whole plant could be regenerated from explants ( any part of plant that taken out and grown under sterile conditions in a special nutritive media). 

So, the correct option is 'Option A' .

Multiple choice botany tissue culture common modes of vegetative propagation plant breeding for food production plant tissue culture

F.C. Steward is associated with

  1. Molecular biology

  2. Genetics

  3. Tissue culture

  4. Immunology
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

F.C. Steward is associated with tissue culture and played an important role in developing the techniques. Caplin and Steward were the first one to use coconut water as a plant growth regulator in the nutrient media. Later on, it was considered as a substitute for cytokinin. He was also involved in the somatic embryogenesis in carrot cell suspension cultures and production of complete plants. He also laid the foundation of micropropagation technique.

So, the correct answer is option C. 

Multiple choice botany tissue culture common modes of vegetative propagation plant breeding for food production plant tissue culture

Callus is

  1. Tissue that forms embryo

  2. An insoluble carbohydrate

  3. Tissue that grows to form embryoid

  4. Unorganised actively dividing mass of cells maintained in culture
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Callus is unorganized actively dividing the mass of cells maintained in culture. It has a meristematic cell which has ample amount of cytoplasm to trigger cell division. It is treated with the growth hormones to allow the cell division and differentiation. Callus when treated with auxin it promotes rooting and when it is treated with cytokinin it stimulates cell maturation, differentiation and finally, promotes the development of stem.

So, the correct answer is option D.

Multiple choice botany tissue culture common modes of vegetative propagation plant breeding for food production plant tissue culture

Callus is _____________.

  1. Tissue that forms embryo

  2. An insoluble carbohydrate

  3. Tissue that grows to from embryoid

  4. Unorganised actively dividing mass of cells maintained in culture
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Callus is defined in plant tissue culture as an unorganized, proliferating mass of parenchyma cells that arises from an explant. It is typically maintained on a culture medium containing specific hormones.

Multiple choice botany tissue culture common modes of vegetative propagation plant breeding for food production plant tissue culture

Electroporation is a technique commonly used in ________________.

  1. Tissue culture

  2. Somatic hybridization

  3. Radioimmuno assay

  4. Electrophoresis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Electroporation is a technique used to introduce foreign DNA into cells by applying a high-voltage electrical pulse to create temporary pores in the cell membrane. It is a standard method in plant and animal tissue culture for transformation.

Multiple choice evs we are special defects of eye disorders of nervous system braille script

Braille cells are

  1. made up of six dots that fit under the fingertips, arranged in two columns of three dots each.

  2. made up of ten dots that fit under the fingertips, arranged in two columns of five dots each.

  3. made up of fourteen dots that fit under the fingertips, arranged in two columns of seven dots each.

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Braille was named after the creator, Louis Braille, a Frenchman who lost his sight as a result of a childhood accident. It involves the usage of 6 dots and the direction is left to right. The paper used is thought as a file folder or index card for proper sensing by the visually impaired people. The characters have rectangular blocks called cells that have tiny bumps called raised dots. The cells are arranged in two columns of three dots each.
So, the correct answer 'made up of six dots that fit under the fingertips, arranged in two columns of three dots each'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Chromonemata are embedded in a

  1. Stroma

  2. Matrix

  3. Sugar

  4. Mucilage
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chromonemata are embedded in the matrix. Chromonemata are the spirally coiled central filament of a chromatid along which the chromomeres are aligned. A chromomere is one of the serially aligned beads or granules of a eukaryotic chromosome, resulting from local coiling of a continuous DNA thread. It is visible on a chromosome during the prophase of meiosis and mitosis. 

So, the correct answer is option B.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

A thread like structure in the nucleus of a cell formed of DNA which carries the genes is

  1. DNA

  2. Genes

  3. Chromosomes

  4. Ribosomes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Deoxyribonucleic acid (DNA) is the information-carrying molecule found in all living organisms. In most animal, plant and fungal cells, DNA is stored in the nucleus coiled up in thread-like structures called chromosomes.

So, the correct answer is option C.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Nucleus contains ________ which are rod shaped structures.

  1. Cytoplasm

  2. Chromosomes

  3. Chromatin

  4. Carbon particles
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chromosomes are thread like structures located inside the nucleus of animal and plant cells. Each chromosome is made of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Choose the correct answer from the alternatives given:
In which part of the cell is DNA concentrated?

  1. Chromosomes

  2. Cell wall

  3. Ribosomes

  4. Golgi body
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The chromosomes are the threadlike structures of nucleic acids found in the nucleus of most of the living organisms, carrying the genetic material in the form of genes. Thus DNA is concentrated in the chromosomes.

B. The cell wall is the structural component of the cell that gives shape to the cell.
C. Ribosomes and the Golgi body are the organelles present in the cell. Ribosomes help ion protein synthesis.
D. Golgi apparatus helps to process and bundle macromolecules like proteins and lipids that are synthesized in the cell.
Hence, the correct answer is 'Chromosomes'.