3.4 Eukaryote Cell Structure

Question 1

What are the parts of a nucleus?

Answer 1

nuclear envelope
nuclear pores
nucleoplasm
chromosomes (RNA)
nucleolus

Question 2

What is the nuclear envelope? And what does it do?

Answer 2

The double membrane that surrounds the nucleus
It controls the entry and exit of materials in and out of the nucleus

Question 3

What are nuclear pores?

Answer 3

Gaps in the nuclear envelope that allow the passage of large molecules (mRNA)
Usually around 3000 pores in each nucleus at 40-100nm in diameter

Question 4

What is nucleoplasm?

Answer 4

Granular, jelly-like material that makes up the bulk of the nucleus

Question 5

What are chromosomes?

Answer 5

protein-bound, linear DNA

Question 6

nucleolus:

Answer 6

small spherical region within the nucleoplasm
Manufactures ribosomal RNA and ribosomes
(there can be more than one nucleolus in the nucleus)

Question 7

What are the functions of the nucleus?

Answer 7

Control centre through production of mRNA and tRNA and therefore protein synthesis
Contains genetic material of the cell as DNA and chromosomes
Manufactures ribosomal RNA and ribosomes

Question 8

What is the function of the mitochondria?

Answer 8

The site of aerobic respiration
Responsible for the production of the energy-carrier molecule - ATP from glucose

Question 9

What are cristae?

Answer 9

The extension in the inner membrane of the mitochondria
Increase the surface area for attachments of enzymes and other proteins involved in respiration

Question 10

What is the matrix?

Answer 10

The remainder of the mitochondrion
Contains protein, lipids, ribosomes and DNA (allows it to produce some of their own proteins)
Where enzymes involved in respiration can be found

Question 11

What do chloroplasts do?

Answer 11

They carry out photosynthesis

Question 12

chloroplast envelope:

Answer 12

The double plasma membrane that surround the chloroplast
Highly selective in what is allowed to enter and leave it

Question 13

grana:

Answer 13

Stacks up to 100 disc-like structures called thylakoids

Question 14

thylakoids:

Answer 14

They are clear disc-like structures that are clear
Allow the light to pass through for photosynthesis to occur

Question 15

rough endoplasmic reticulum (RER):

Answer 15

cell membrane that has ribosomes present on the surface of it
provides a large surface area for the synthesis of proteins
provides a pathway for the transport of material throughout the cell

Question 16

smooth endoplasmic reticulum (SER):

Answer 16

cell membrane that synthesis, stores and transports lipids
synthesises, stores and transports carbohydrates

Question 17

golgi apparatus:

Answer 17

proteins and lipids produced by ER pass through in a strict sequence
modifies proteins by adding non protein components (CHO)
sorts them and sends them to the correct destination

Question 18

function of the golgi apparatus:

Answer 18

add CHO to proteins to produce glycoproteins
produce secretory enzymes
secretes CHO, like those used in making cell walls
transport, modify and store lipids
form lysosomes

Question 19

vesicles:

Answer 19

structures formed by the ER
transport the lipids and proteins
passes through golgi apparatus
transports modified molecules

Question 20

lysosomes:

Answer 20

vesicles produced by the golgi apparatus
contains enzymes such as proteases and lipases and lysozymes

Question 21

function of lysosomes:

Answer 21

-hydrolyse material ingested by phagocytic cells (white blood cells)
-release enzymes to the outside of the cell (exocytosis) in order to destroy material around the cell
-digest worn out organelles so useful chemicals can be reused
-completely break down cells after they have died (autolysis)

Question 22

ribosomes:

Answer 22

in charge of proteins synthesis

Question 23

where can ribosomes be found?

Answer 23

cytoplasm or on the surface of the rough endoplasmic reticulum

Question 24

types of ribosomes + where they’re found:

Answer 24

80S - found in eukaryotic cells (25nm in diameter)
70S - found in prokaryotic cells, mitochondria and chloroplasts, slightly smaller

Question 25

cell wall + function:

Answer 25

consists of polysaccharides, cellulose
provides structural strength to the plant cell
stops them from bursting under pressure created by the osmotic entry of water
allows water to pass along it

Question 26

middle lamella:

Answer 26

thin layer that marks the boundary between adjacent cell walls and cements them together

Question 27

vacuole:

Answer 27

contains a solution of mineral salts, sugars, amino acids, wastes and sometimes pigments

Question 28

functions of the vacuoles:

Answer 28

support herbaceous plants, and parts of woody plants, makes cells turgid
sugars and amino acids can act as temporary food store
pigments may colour petals (attracting pollinating insects)