Cell: Unit of Life

Question 1

Nucleus: discovered by

Answer 1

Robert Brown

Question 2

Nucleus: functions

Answer 2

1. carrying genetic information from one cell generation to the next
2. controls all metabolic activies of the cell by controlling the synthesis of enzymes

Question 3

Chromosomes: discovered by

Answer 3

Strasburger

Question 4

Chromosomes: term coined by

Answer 4

Waldeyer

Question 5

Centromere

Answer 5

Primary constriction seen on a chromosome

Question 6

Karyotype

Answer 6

The group of characteristics that identifies a particular chromosome set

Question 7

Mitochondria: discovered by

Answer 7

Kolliker

Question 8

Why are mitochondria called the powerhouse of the cell?

Answer 8

• Their primary function is the conversion and transfer of cellular energy
• They have the capacity of converting the potential energy of various food materials into the form of energy that can be used by cells to carry out various activities

Question 9

Plastids (classify based on colour)

Answer 9

1. Chloroplasts- green
2. Leucoplasts- colourless
3. Chromoplasts- coloured

Question 10

Leucoplasts- functions

Answer 10

function as storage organelles and
store starch- amyloplasts
store oil- elaioplasts
store proteins- aleuroplasts

Question 11

Chromoplasts

Answer 11

Plastids that mainly store carotenoids are called chromoplasts. They are found in flowers and fruits.

Question 12

Chloroplasts- function

Answer 12

1. Contain the green pigment chlorophyll which helps in the production of chemical energy by the process of photosynthesis.
2. Contain quantosomes on the inner surface of the lamellar membrane which absorb a mole quantum of light

Question 13

Structural and functional unit of chloroplasts

Answer 13

Quantosomes

Question 14

Endomembrane structures

Answer 14

4 structures are collectively called the endomembrane structures because they form the endoskeleton of the cell:
1. Endoplasmic reticulum
2. Golgi apparatus
3. Lysosomes
4. Vacuoles

Question 15

Two types of endoplasmic reticulum

Answer 15

1. Rough endoplasmic reticulum-
   - protein synthesis and transport
   - ribosomes lie on the outer border of its membrane
2. Smooth endoplasmic reticulum-
   - synthesis of glycolipids
   - devoid of ribosomes

Question 16

Golgi complex: discovered by

Answer 16

Camillo Golgi

Question 17

Golgi complex: function

Answer 17

1. Secretion
2. Formation of lysosomes

Question 18

Lysosomes were discovered by

Answer 18

Christian de Duve

Question 19

Why are lysosomes called the suicide bags of the cell?

Answer 19

Lysosomes contain powerful enzymes that digest the cell contents along with the foreign substance

Question 20

Lysosomes: functions

Answer 20

1. Intracellular digestion
2. Destruction of certain structures during the process of development

Question 21

Membrane surrounding a vacuole

Answer 21

Tonoplast

Question 22

Two types of vacuoles

Answer 22

Contractile: contract and release the extra fluid and salt from the cell

Food vacuoles: reserve food material

Question 23

List the microbodies and their functions

Answer 23

1. Glyoxysomes: main function is to convert fatty acids to acetyl CoA
2. Peroxisomes: They contain the enzyme catalase which helps in the breakdown of the highly toxic H₂O₂ into water and oxygen
   H₂O₂ —-catalase—-> H₂O + [O]
3. Spherosomes: storage and transport of lipids

Question 24

Ribosomes: discovered by

Answer 24

Palade

Question 25

Location of ribosomes

Answer 25

• mainly seen on the surface of rough ER
• also seen scattered in the cytoplasm

Question 26

Svedberg Unit

Answer 26

Stands for the sedimentation coefficient

Question 27

Ribosomes seen in eukaryotes

Answer 27

70s ribosomes

Question 28

Ribosomes seen in prokaryotes

Answer 28

80s ribosomes

Question 29

Ribosomes: functions

Answer 29

protein synthesis

Question 30

Polyribosomes/polysomes

Answer 30

Ribosomes seen in clusters are called polyribosomes

Question 31

Centrioles: composition

Answer 31

A centriole is made up of nine triplets of microtubules composed of tubulin protein

Question 32

Centriole: function

Answer 32

Help in cell division

Question 33

Centriole: location

Answer 33

Seen on either side of the spindle fibres

Question 34

Tight junctions

Answer 34

In cell membranes, seal gaps between epithelial cells

Question 35

Gap junctions

Answer 35

In cell membranes, allow the passage of small water molecules from cell to cell

Question 36

Adherens junction

Answer 36

Connect actin filament bundles in one cell with that of the other cell

Question 37

Glycocalyx

Answer 37

An animal cell does not have a cell wall, instead it has a cell coat made of short carbohydrate chains. This cell coat is called glycocalyx

Question 38

Desmosomes

Answer 38

Thickened regions of the plasma membrane which permit intracellular electrical communication of inorganic ions

Question 39

Facilitated diffusion

Answer 39

the process of spontaneous passive transport of molecules or ions
across a biological membrane
via specific trans-membrane integral proteins
like carrier proteins or channel proteins

Question 40

Uniport transfer

Answer 40

Uniport transfer is when one ion or molecule crosses the protoplasmic membrane at one site
Example: Transfer of glucose molecule into the cell.

Question 41

Symport transfer

Answer 41

Symport transfer is when two ions or molecules cross the protoplasmic membrane at the same time in the same direction
Example: Entry of glucose and Na molecule into the cell in the same direction

Question 42

Antiport transfer

Answer 42

Antiport transfer is when two ions or molecules cross the protoplasmic membrane at the same time in the opposite direction.
Example: Transport of Na and K molecules across the membrane in opposite directions