1.2 Cell organelles

Question 1

What is the advantage of having membrane bound organelles?

Answer 1

Potentially harmful chemicals are isolated and molecules with specific functions can be concentrated in one area.

Question 2

Membranes provide a large surface area for what?

Answer 2

The attachment of enzymes involved in metabolic processes.

Question 3

What are all the organelles in an animal cell?

Answer 3

Cell membrane, centrosome, lysosome, cytoplasm, rough ER, smooth ER, ribosomes, golgi body, vacuole, mitochondria and nucleus.

Question 4

What are all the organelles in a plant cell?

Answer 4

Plasmodesmata, RER, SER, nucleus, ribosomes, golgi body, mitochondria, peroxisome, plastid, chloroplast, cytoskeleton, central vacuole, cytoplasm, plasma membrane and cell wall.

Question 5

How big is the nucleus in diameter?

Answer 5

10-20 µm.

Question 6

What is the nuclear membrane?

Answer 6

A double membrane that surrounds the nucleus.

Question 7

What is the purpose of the nuclear pores?

Answer 7

Allow the passage of mRNA and ribosomes between the nucleus and the cytoplasm.

Question 8

What is the function of the nucleolus?

Answer 8

Synthesise the components of ribosomes and make RNA (tRNA and rRNA).

Question 9

What is the nucleoplasm?

Answer 9

Granular material that contains chromatin.

Question 10

What does chromatin consist of?

Answer 10

DNA molecules bound with proteins called histones.

Question 11

What is the function of the nucleus?

Answer 11

Contains DNA that codes for protein synthesis.

Question 12

What occurs in the nucleus?

Answer 12

DNA replication.

Question 13

How big is the mitochondria?

Answer 13

1-10 µm.

Question 14

Mitochondria are the sites of what?

Answer 14

Aerobic respiration.

Question 15

The mitochondria are surrounded by what?

Answer 15

A double membrane.

Question 16

The inner membrane of the mitochondria is folded into what?

Answer 16

Cristae.

Question 17

Why is the inner membrane of the mitochondria folded?

Answer 17

To increase surface area.

Question 18

What is the matrix in a mitochondria?

Answer 18

Liquid that fills cristae.

Question 19

What does the matrix in the mitochondria contain?

Answer 19

Enzymes involved in the Krebbs cycle.

Question 20

What size are the ribosomes in the mitochondria?

Answer 20

70S.

Question 21

What does the mitochondria contain for proteins and self-replication?

Answer 21

A small circle of DNA.

Question 22

What is the function of the chloroplast?

Answer 22

To trap light energy which is used to synthesize carbohydrates.

Question 23

What is the stroma in chloroplasts?

Answer 23

Fluid found between double membrane.

Question 24

What does the stroma contain?

Answer 24

Ribosomes, lipids and circular DNA.

Question 25

What are thylakoids in chloroplasts?

Answer 25

Flattened sacs within the stroma.

Question 26

What is a granum in a chloroplast?

Answer 26

Name for a stack of thylakoids ( 2 ~ 100).

Question 27

What do the stacks of thylakoids allow?

Answer 27

Bigger surface area for trapping light energy.

Question 28

What is the function of the endoplasmic reticulum?

Answer 28

Allows transport of materials through the cell.

Question 29

What does the rough ER have that the smooth ER doesn't?

Answer 29

Ribosomes on it's surface.

Question 30

What is the function of the rough ER?

Answer 30

Manufacturing and transport of proteins. It also produces transport vesicles which merge to form the golgi body.

Question 31

What is the function of the smooth ER?

Answer 31

Synthesis, packaging and transport of lipids.

Question 32

What does the golgi body consist of?

Answer 32

A number of flattened membrane-bound sacs in which proteins and other molecules are modified.

Question 33

What is the functions of the golgi body?

Answer 33

- producing secretory enzymes that are packaged into secretory vessels. - secreting carbohydrates - producing glycoprotein - transporting and storing lipids - forming lysosomes containing digestive enzyme

Question 34

How is the golgi body formed?

Answer 34

By the Rough ER being pinched off at the ends to form small vesicles - some vesicles join to form the golgi body.

Question 35

How do vesicles pinched off the other end of the golgi body secrete their contents?

Answer 35

Via exocytosis when they fuse with the cell membrane.

Question 36

What are ribosomes?

Answer 36

Sites of protein synthesis.

Question 37

Where are ribosomes found?

Answer 37

Free within the cytoplasm or attached to the endoplasmic reticulum.

Question 38

What are ribosome subunits made of?

Answer 38

rRNA and protein.

Question 39

How many subunits do ribosomes consist of?

Answer 39

2.

Question 40

Where are the sub units for ribosomes manufactured?

Answer 40

In the nucleolus.

Question 41

How big are ribosomes in prokaryotic cells?

Answer 41

70S.

Question 42

How big are ribosomes in eukaryotic cells?

Answer 42

80S.

Question 43

Lysosomes are surrounded by what?

Answer 43

A single membrane.

Question 44

Where are lysosomes formed?

Answer 44

In the golgi body.

Question 45

What do lysosomes contain?

Answer 45

Digestive enzymes that break down cellular waste and debris.

Question 46

How are lysosomes formed?

Answer 46

Formed when portions of the golgi body are pinched off.

Question 47

What is the function of the lysosomes?

Answer 47

To contain and isolate digestive enzymes from the rest of the cell.

Question 48

What are the traits of vacuoles in animal cells?

Answer 48

Small, temporary and may occur in large numbers.

Question 49

What are the traits of vacuoles in plant cells?

Answer 49

large and permanent fluid-filled sac bounded by a single membrane called the tonoplast.

Question 50

What does the vacuole in the plant cell contain?

Answer 50

Cell sap.

Question 51

What does the vacuole in the plant cell store?

Answer 51

Chemicals such as glucose.

Question 52

What does the vacuole provide?

Answer 52

Provide an osmatic system to support young tissue.

Question 53

Where do centrioles occur?

Answer 53

In all animal cells and most protoctistans but not in cells of higher plants.

Question 54

Where are centrioles located?

Answer 54

Just outside the nucleus.

Question 55

What are centrioles?

Answer 55

Two rings of microtubules, making hollow cylinders positioned at right angles to one another.

Question 56

What are two centrioles sometimes called?

Answer 56

The centrosome.

Question 57

What do the centrioles do in cell division?

Answer 57

Organise the microtubules that make the spindle.

Question 58

What are the functions of the cellulose cell wall?

Answer 58

- Provides strength and support - Permits the movement of water from cell to cell

Question 59

What does the cell wall consist of?

Answer 59

Cellulose microfibrils embedded in a polysaccharide matrix.

Question 60

What are the three main functions of the cell wall?

Answer 60

- Transport - Mechanical Strength - Communication Between Cells

Question 61

Why is the cell wall fully permeable to water and dissolved substances?

Answer 61

Gaps between the cellulose fibres.

Question 62

Why is the cell wall very strong?

Answer 62

Due to the laminated arrangement and structure of cellulose micro fibrils.

Question 63

How does the plasmodesmata form?

Answer 63

The plasmodesma occurs where there is no cellulose thickening between two cells.

Question 64

What is the network of cytoplasm in connected cells called?

Answer 64

A symplast.