Cell And Nucleus(chap1)

Question 1

Why is there a very little variation in cellular architecture of different species

Answer 1

Because all organisms originated from a single unicellular organism

Question 2

Total number of cell present in the human body

Answer 2

75 trillion cells

Question 3

What is responsible for the activities that happens between extra cellular compartments and intracellular compartments

Answer 3

Cell membrane

Question 4

The components of cell ( in terms of organic and inorganic components) and the percentage of each in the mass of a cell

Answer 4

1. Water : 70-75%
2. Electrolytes
3. Lipid : 2%
4. Carbohydrates : 1%
5. Protein : 10-20%

Question 5

What does water helps in cellular function

Answer 5

In the transport of substances from one part to another
Chemical reaction occurring in cell take place in solution of water

Question 6

What are the major electrolytes and which ones are mainly inside and outside the cell

Answer 6

. Potassium, magnesium and phosphate are mainly present inside the cell

. Sodium and chloride are mainly present outside the cell

. Calcium, sulphate and bicarbonate are also part of the major electrolytes of the cell

Question 7

Main function of electrolytes

Answer 7

Regulation of water balance
Contraction and relaxation of muscle
Transmission of nerve impulses
In short it helps in cellular control mechanisms.

Question 8

Types of protein (in terms of structure)

Answer 8

Globular protein
Structural protein

Question 9

Features of globular proteins

Answer 9

. Globular or shaped like a ball in structure
. Made of individual protein molecules
. Found in mainly enzymes that catalyse various chemical reactions

Question 10

What is the basic structural and functional unit of all living organisms?

Answer 10

Cell

Question 11

Which organelle is known as the powerhouse of the cell?

Answer 11

Mitochondria

Question 12

Which organelle is responsible for protein synthesis?

Answer 12

Ribosomes

Question 13

What is the function of the endoplasmic reticulum (ER) in a cell?

Answer 13

Involved in protein and lipid synthesis

Question 14

What is the function of the chloroplast in a plant cell?

Answer 14

Site of photosynthesis, where sunlight is converted into energy

Question 15

Which organelle is involved in intracellular digestion and recycling of cellular components?

Answer 15

Vacuole

Question 16

What is the function of the cell membrane in a cell?

Answer 16

Regulates the movement of substances into and out of the cell

Question 17

Which organelle is involved in maintaining cell turgidity and storing water in plant cells?

Answer 17

Central vacuole

Question 18

Which organelle is responsible for maintaining cell shape and movement in animal cells?

Answer 18

Cytoskeleton

Question 19

What is the function of the nuclear membrane in a cell?

Answer 19

Surrounds the nucleus and controls the flow of molecules in and out

Question 20

Which organelle is responsible for converting sunlight into energy in plant cells?

Answer 20

Chloroplasts

Question 21

What is the function of the flagella in a cell?

Answer 21

Helps in cell movement

Question 22

What is the function of the cilia in a cell?

Answer 22

Helps in attachment of cells and moving substances along the cell surface

Question 23

What is structural proteins do

Answer 23

. Polymer of proteins molecules
. Long filament form
.provide contractile mechanisms for muscle
. Cytoskeleton of cilia axon
Found in collagen and elastic fibre

Question 24

Short note on each water, electrolytes, proteins, lipid and carbohydrates

Answer 24

Page no. 4 and 5

Question 25

What are major parts of cell

Answer 25

Nucleus Cytoplasm Cell membrane

Question 26

What is the thickness of cell membrane

Answer 26

7-10nm

Question 27

Composition of cell membrane

Answer 27

Protein: 55% Phospholipids: 25% Cholesterol: 13% Other lipid: 4% Carbohydrates: 3%

Question 28

Which model of the cell membrane is most accepted

Answer 28

The fluid mosaics model purposed by singer and nicolson is the most accepted

Question 29

What are the two main lipid in the cell membrane and what r its hydrophobic and hydrophilic parts

Answer 29

1.Phospholipid: phosphate- hydrophilic part Fatty acid- hydrophobic 2. Cholesterol: Hydroxyl- hydrophilic Steroid nucleus- hydrophobic

Question 30

What r the position of the hydrophobic and hydrophilic parts of the cell membrane and which substances are permeable

Answer 30

. Hydrophobic lies towards the centre of the cell membrane . Hydrophilic faces towards the surrounding water . Water soluble substances such as ions and glucose are impermeable while lipid soluble substances such as alcohol and oxygen are permeable

Question 31

Function of lipid

Answer 31

. Forms the cell membrane . Selectively permeability as fat soluble substances are permeable while water soluble substances r not . Provides framework for the attachment of proteins and carbohydrates

Question 32

What are the two types of proteins present in cell membrane

Answer 32

Integral proteins: passes through the entire thickness of membrane and closely associated with the membrane lipid Peripheral proteins: attached only to the surface and help in maintaining the cell shape and motility

Question 33

Function of proteins

Answer 33

.Provide framework to cell .helps in maintaining shape as well as motility of cell .acts pump which helps in active transport .acts as enzymes, receptors and ion channels .also acts as carriers for facilitated diffusion

Question 34

What is the thin layer of carbohydrates molecules through out of the surface of cell membrane called

Answer 34

Glycocalyx

Question 35

Function of carbohydrates in cell membrane

Answer 35

Attached to other cell membrane’s glycocalyx .act as receptors for binding hormones . Participate in immune reaction

Question 36

What is the central of the cell and what does it do

Answer 36

Nucleus Controls the chemical reaction occurring in the cell and cell reproduction

Question 37

What are the main part of nucleus are and what are composition of nucleus in dry weight

Answer 37

Main parts are nucleolus and chromatin material In dry weight: 80% protein 18% DNA 2% RNA

Question 38

What is chromatin

Answer 38

The nucleus contain densely staining network of dna and proteins which during cell division is identified as chromosome

Question 39

What is the unit of heredity and how many chromosome are present in human

Answer 39

Gene r the unit of heredity and humans have 23pair of chromosome

Question 40

Short note on nuclear membrane

Answer 40

The nuclear membrane has a outer and inner nuclear membrane. The outer membrane is continuous with endoplasmic reticulum (ER). The membrane contains thousands of nucleus pores which is 9nm in diameter as it allows only small weights molecules to pass through

Question 41

Short note on nucleoli

Answer 41

Nucleoli is the lightly stained structure stored in the nucleus. They synthesise and store rna and protein molecules which later on transporting forms mature ribosome Nucleoli: plural Nucleolus: singular

Question 42

What is cytoplasm and does it contain

Answer 42

The entire region between the cell membrane and nucleus. It contains . Cytosol .cell organelles .cytoskeleton .inclusion bodies

Question 43

What is cytosol

Answer 43

It is the fluid portion in cytoplasm where cell organelles are present

Question 44

Which cell contains multiple nucleus and which contains none

Answer 44

Multiple : skeletal muscle None: matured RBCs

Question 45

Structure of nucleus

Answer 45

Usually a nucleus is spherical in shape and is located near the centre of the cell. The nucleus covered with the nucleus envelope and the enclosed space is called as nucleoplasm in which nucleolus is present The nucleolus is an organised structure of RNA, DNA and proteins that synthesis ribosomal RNA. The remaining DNA is dispersed across the nucleoplasm called the chromatin fibre which during mitosis turns into a discrete structure called chromosomes