Chapter 2 - Cells

Question 1

What is the cell theory?

Answer 1

Cells are the basic structural and functional units of all living organisms.

Question 2

What is the cell membrane, its function and its main structure?

3

Answer 2

• cell’s outer boundary
• separates the cell’s contents from the external environment/neighbouring cells.
• regulates the passage of materials.

Question 3

What is the Golgi body and its function?

3

Answer 3

• consists of flattened, membranous bags stacked on top of each other
• modifies SOME proteins and packages them in vesicles (vesicles are pinched off from the edges of its membrane/from the rough ER/from the cell membrane) for secretion from cell
• usually located near the nucleus.

Question 4

What is the cytoplasm and its function?

3

dissolved, several

Answer 4

• A matrix in which several organelles are suspended
• contains several dissolved substances
• carries out several important biochemical processes such as mitosis.

Question 5

What is the cytosol and its function?

5

mr,op,foc

Answer 5

• The liquid component of the cytoplasm
• 75-90% water with a complex mixture of dissolved substances such as salts and carbohydrates, and suspended non-soluble compounds like proteins and fats
• where most of the metabolic reactions occur
• controls the osmotic pressure of the cell
• controls the flow of chemicals into and out of the cell

Question 6

What is an organelle?

mb

Answer 6

A structure found in the cell that is usually membrane-bound (except ribosome and nucleolus) that carries out a specific function.

Question 7

List all the organelles.

13

Answer 7

• cell membrane
• cytoplasm
• vesicle
• ribosome
• Golgi body
• mitochondria
• nucleus
• nucleolus
• lysosomes
• cytoskeleton
• inclusions
• endoplasmic reticulum
• centrioles.

Question 8

What is the nucleus and its function?

2

m.e

Answer 8

• The membrane-enclosed organelle within a cell that contains the genetic material for the cell (DNA)
• Controls the activity of the cell including the way it functions.

Question 9

What is the nucleolus and its function?

2

ss,manu

Answer 9

• A spherical structure found in the cell’s nucleus, suspended in nucleoplasm
• Responsible for the manufacture of ribosomal RNA, to create ribosomes.

Question 10

What are ribosomes, their function and location?

3

Answer 10

• Very small, spherical organelles
• At the ribosomes, amino acids are joined together to make proteins (they facilitate the synthesis of protein in cells)
• Found free in the cytoplasm or attached to membranes within the cell e.g. the endoplasmic reticulum.

Question 11

What is the endoplasmic reticulum and its function?

2

popm,ext,prov.

Answer 11

• The network of channels formed by pairs of parallel membranes that extend from the cell membrane, through the cytoplasm of the cell, and to the nuclear membrane
• Function is to provide a surface for chemical reactions

Question 12

What are lysosomes and their function?

5

join

Answer 12

• Small spheres, bound by a membrane
• Formed from the Golgi body
• Contain digestive enzymes that can break down large molecules
• Can join with vesicles that contain particles/liquids (entering the cell) and break down the material inside
• Digest worn out organelles.

Question 13

What are the mitochondria and their function?

5

SSEHT

Answer 13

• Spherical shaped structures
• Spread out throughout the cytoplasm
• Each has a double membrane; the smooth outer membrane surrounds the mitochondrion, while the inner membrane, the cristae, is arranged into a series of folds that extend into the interior of the organelle
• Hosts some of the chemical reactions of cellular respiration
• The folding of the cristae produces a large surface area for these reactions to take place

Question 14

What are cilia/flagella and their function? Give examples of where they can be found.

Answer 14

Cilia: Short and numerous fine projections that can beat back and forth to move the whole cell or substances over the cell surface. (the cells lining the trachea, they move mucus and trapped particles towards the throat)

Flagella: Long fine projections (only 1 or 2) that can beat back and forth to move the whole cell or substances over the cell surface. (sperm cell, allows sperm to swim to egg)

Question 15

What is the cytoskeleton and its function?

4

AGCC - fr,pf,mt,mfl

Answer 15

• A framework of protein fibres
• Gives the cell its shape and assists cell movement
• Consists of microtubules (hollow rods that keep organelles in place or move them around the cell)
• Consists of microfilaments (which move materials around the cytoplasm or move the whole cell)

Question 16

What is the current model of the cell membrane?

2

Answer 16

The fluid mosaic model:
- Membrane molecules always moving
- Composed of many different kinds of molecules

Question 17

What are vesicles, their function and location?

2

mb, transport

Answer 17

• Small membrane-bound sacs that transport materials into, out of or within the cell
• Located next to the endoplasmic reticulum and near the cell nucleus

Question 18

What is the difference between rough endoplasmic reticulum and smooth endoplasmic reticulum?

Answer 18

Rough ER - when ribosomes are attahed to the outside of some membranes
Smooth ER - when there are no ribosomes attached to the outside

Question 19

What are inclusions?

cs

Answer 19

Chemical substances that aren’t part of the cell structure but are found in the cytoplasm of the cell (e.g. haemoglobin, melanin pigment of skin, red pigment in red blood cells)

Question 20

What are centrioles?

repro

Answer 20

A pair of cylindrical structures, usually located near nucleus. It is involved in the reproduction of the cell.