Cellular Biology

Question 1

What are the 3 main parts to a cell?

Answer 1

1) the plasma membrane 2) the cytoplasm 3) the nucleus

Question 2

What is the phospholipid bilayer?

Answer 2

Is permeable to water, gases, steroids and fat soluble vitamins

Question 3

What do integral proteins do?

Answer 3

Assist small and medium sized water soluble substances across the membrane. They also act as a receptor for substances such as insulin

Question 4

What are channel proteins?

Answer 4

Allow certain ions to move in and out of the cell

Question 5

What are carrier proteins?

Answer 5

Change the shape as they move substances across the membrane

Question 6

What are passive transport processes?

Answer 6

These do not consume energy (ATP) and move with the concentration gradient

Question 7

What are examples of passive transport processes?

Answer 7

Diffusion and osmosis

Question 8

What is simple diffusion?

Answer 8

Occurs when gases move across the phospholipid bilayer from a high concentration to a low concentration

Question 9

What is facilitated diffusion?

Answer 9

Gases are assisted by channel and carrier proteins to move from high concentration to low concentration

Question 10

What is osmosis?

Answer 10

Water moves across a selectively permeable membrane from an area of high water concentration to an area of low water concentration

Question 11

What are active transport processes?

Answer 11

These use ATP and move against a concentration gradient

Question 12

What are examples of active transport processes?

Answer 12

Active transport, Endocytosis and Exocytosis

Question 13

What is active transport?

Answer 13

It requires ATP to push the gas into the cell. The most important active transport pump exchanges Na+ and K+ ions across the cell membrane to maintain homeostasis

Question 14

What is endocytosis?

Answer 14

This involves phagocytosis (‘eating’ dead cells and bacteria) or pinocytosis (‘drinking’)

Question 15

What is exocytosis?

Answer 15

Works in the opposite way to endocytosis and enables neurotransmitters, hormones, mucus and digestive enzymes

Question 16

What is the cytoskeleton?

Answer 16

Helps to maintain the cells shape, holds organelles in place, enables cell contraction, cell division and enables the function of microvilli, cilia and flagella

Question 17

What are the 6 main organelles?

Answer 17

1) Ribosomes 2) Endoplasmic Reticulum (ER) 3) Golgi body/ complex 4) Mitochondria 5) Lysosomes and 6) Nucleus

Question 18

What are ribosomes?

Answer 18

They manufacture proteins in response to messages (mRNA) from the nucleus. Ribosomes attach to the ER and make proteins for export

Question 19

What is the endoplasmic reticulum (ER)?

Answer 19

This is a network of folded membrane extends throughout the cytoplasm.

Question 20

What does smooth ER do?

Answer 20

Makes lipids, steroidal hormones, detoxifies drugs and breaks down glycogen to glucose

Question 21

What does rough ER do?

Answer 21

Makes proteins and phospholipids

Question 22

What is the Golgi body?

Answer 22

Its main job is to concentrate, modify and package proteins and lipids for export or use in the cell membrane

Question 23

What is the mitochondria?

Answer 23

These are complex organelles, with 2 layers of membrane that make ATP. They have their own DNA, RNA and ribosomes and are able to reproduce themselves

Question 24

What are lysosomes?

Answer 24

These spherical membranous organelles are the cells demolition crew. They destroy bacteria, viruses, toxins and damaged organelles. They release calcium from the bones and glucose from glycogen. They break down unwanted tissue such as the uterine lining and webs between digits in the foetuses

Question 25

What is the nucleus?

Answer 25

The control centre of the cell. Is round or oval and is usually the most prominent organelle. Most cells have a single nucleus often in the centre of the cell

Question 26

What does the nucleus consist of?

Answer 26

1) The nuclear envelope 2) the nucleoli 3) nucleoplasm and 4) chromatin

Question 27

What is the nuclear envelope?

Answer 27

This double membrane layer is similar to the mitochondria membrane. the outer layer is continuous with the rough ER and studded with ribosomes. It is punctured with nuclear pores

Question 28

What is the nucleoli?

Answer 28

Typically there are 1 or 2 nucleoli per nucleus. Their job is to manufacture ribosomal subunits, these leave through the nuclear pores and combine to make ribosomes in the cytoplasm

Question 29

What is nucleoplasm?

Answer 29

Is a jellylike fluid in which the other nuclear elements are suspended. It is similar to cytosol

Question 30

What is chromatin?

Answer 30

The nucleus contains 46 chromosomes. In non dividing cells the chromosomes unwind to become chromatin. The total genetic information in cell is its genome