Cell Structure And Functions

Question 1

What is the outermost membrane of a cell?
What is it composed of?

Answer 1

Plasma membrane
Phospholipid bilayer

Question 2

What is the glycocalyx?

Answer 2

Glycoproteins and glycolipids that project from the plasma membrane

Question 3

What is a function of the glycocalyx?

Answer 3

Protect the cell from the immune system - shows immunogenicity

Question 4

What are some functions of the plasma membrane?

Answer 4

• cell recognition and adhesion
• compartmentalisation
• selective permeability
• endocytosis
• exocytosis

Question 5

What is exocytosis?

Answer 5

Vesicles fusing with the plasma membrane and releasing their contents to the outside

Question 6

What is endocytosis?

Answer 6

Capturing a substance or particle from outside the cell by engulfing it with the cell membrane, and bringing it into the cell

Question 7

What does the nucleus contain?

Answer 7

DNA, RNA and nucleoproteins (ribosomes)

Question 8

What is the dense part of the nucleus?
How would you identify it using a TEM?

Answer 8

Heterochromatin - not active in RNA synthesis
Darker part

Question 9

What is the less dense part of the nucleus?

Answer 9

Euchromatin - active in RNA synthesis

Question 10

What happens in the nucleolus?

Answer 10

Site of ribosomal RNA synthesis

Question 11

What allows the ribosomal subunits to leave the nucleolus?

Answer 11

Nuclear pores

Question 12

Where are ribosomes assembled?

Answer 12

Rough ER

Question 13

What is the nuclear envelope a type of?

Answer 13

Specialised ER

Question 14

Function of RER

Answer 14

Site of ribosomes
Site of protein synthesis

Question 15

Function of SER (2 specific)

Answer 15

Lipid biosynthesis
Intracellular transport

N-linked glycosylation
Disulphide bond formation

Question 16

Function of Golgi apparatus

Answer 16

Receives proteins at cis face
Modifies them
Sorts and packages them into vesicles
Proteins leave via trans face

Question 17

What is the cis face of the Golgi body?

Answer 17

Outer part
Where substances enter from the endoplasmic reticulum for processing

Question 18

What is the trans face of a Golgi body?

Answer 18

Inner part
Where vesicles detach to assemble into lysosome, secretion or further processing

Question 19

What do lysosomes contain?

Answer 19

Acid hydrolases

Question 20

What are lysosomes that have digested their contents by contain indigestible remnants called?

Answer 20

Residual bodies

Question 21

Where are peroxisomes high in number?

Answer 21

Kidney and liver
They modify toxic molecules before re entering the blood stream

Question 22

What are peroxisomes that site of?

Answer 22

Oxygen utilisation
Peroxide production

Question 23

What are the folds of the inner membrane in mitochondria called?

Answer 23

Cristae

Question 24

Function of mitochondria (2)

Answer 24

Site of of ATP production by oxidative phosphorylation

Act as a Ca2+ store

Question 25

What is the inner space of mitochondria called? What does it contain?

Answer 25

Matrix Enzymes of krebs and fatty acid cycles

Question 26

What is special about mitochondria?

Answer 26

You inherit all mitochondria from your mother

Question 27

Three main types of cytoskeleton

Answer 27

Microfilaments Intermediate filaments Microtubules

Question 28

Function of cytoskeleton

Answer 28

- structural support for plasma membrane and organelles - provides means of movement for organelles

Question 29

What do Microfilaments bind to to allow contraction?

Answer 29

ATP

Question 30

Function of intermediate filaments

Answer 30

Tough supporting mesh work in the cytoplasm They hold the cell together and prevent lysis

Question 31

Function of microtubules

Answer 31

Originate from centrosome Attachment proteins can bind to organelles and move them along the microtubules

Question 32

Why wouldn’t there be a nuclear envelope?

Answer 32

In prophase It breaks down To release chromosomes

Question 33

What is the function of the phospholipid bilayer? (4)

Answer 33

- Allows for selective permeability - Exocytosis and endocytosis - Recognition - Adhesion

Question 34

What type of molecule is a phospholipid? What does this mean?

Answer 34

Amphipathic - has a polar head and non-polar tail

Question 35

What are the two types of secretion from Golgi apparatus?

Answer 35

Constitutive Signal mediated

Question 36

What does constitutive secretion mean?

Answer 36

Continuous

Question 37

What is the cell coat of a lysosome called? What is it made of? What is its function?

Answer 37

Glycocalyx Polysaccharides and oligosaccharides Stops lysozymes digesting the cell