Cell Structure and Transport

Question 1

What is the maximum resolution of the light microscope and the electron microscope?

Answer 1

Light = 200nm
Electron = 0.1nm

Question 2

What is the maximum magnification of the light, SEM and TEM microscopes?

Answer 2

Light = x1500
SEM = x100000
TEM = x500000

Question 3

Actual Size = ?

Answer 3

Image Size/Magnification

Question 4

Magnification = ?

Answer 4

Image Size/Actual Size

Question 5

What is resolution?

Answer 5

The ability to distinguish between 2 separate points clearly.

Question 6

What is magnification?

Answer 6

The state of something being magnified or represented by an amplified image.

Question 7

Outline the roles of cytoskeleton?

Answer 7

• Maintains the shape of the cell
• Allows movement of organelles
• Supports the cell

Question 8

What are the role of vesicles?

Answer 8

Transport many different materials around the cell.

Question 9

Structure of nucleus?

Answer 9

• Surrounded by nuclear envelope
• Nuclear pores in the nuclear envelope
• Nucleolus in the nucleus
• Has chromatin

Question 10

What is the role of nucleus?

Answer 10

• Houses genetic info
• Contains chromatin that condenses during mitosis
• Nucleolus makes RNA and ribosomes

Question 11

Structure of Rough Endoplasmic Reticulum?

Answer 11

• Flattened sacs called cisternae
• Joined to the outer nuclear membrane
• Littered with ribosomes that make proteins.

Question 12

Structure of Smooth Endoplasmic Reticulum?

Answer 12

Same as Rough Endoplasmic Reticulum only without ribosomes.

Question 13

What is the role of Smooth Endoplasmic Reticulum?

Answer 13

Involved in making lipids that the cell needs.

Question 14

Structure of Golgi body?

Answer 14

Flat membrane-bound sacs(stacked)

Question 15

Role of Golgi body?

Answer 15

Modification of proteins and transport of said proteins in vesicles.

Question 16

Structure of mitochondria?

Answer 16

2 membranes separated by fluid filled space.
Inner membrane is highly folded to form cristae.
Central part is called matrix.

Question 17

Role of mitochondria?

Answer 17

Produces ATP.

Question 18

Structure of chloroplast?

Answer 18

2 membrane separated by fluid filled space.

Inner membrane is continuous, containing flattened membrane sacs called thylakoids(stack=granum/grana)

Question 19

Role of chloroplast?

Answer 19

Site of photosynthesis.

Question 20

Structure of lysosomes?

Answer 20

Single membrane, spherical sacs.

Question 21

Role of lysosomes?

Answer 21

Contain powerful digestive enzymes, used to break down foreign objects/bacteria etc.

Question 22

Where are ribosomes located?

Answer 22

Some are free in cell and some bound to rough endoplasmic reticulum.

Question 23

Role of ribosomes?

Answer 23

Site of protein synthesis.

Question 24

Structure of centrioles?

Answer 24

Small tubes of protein fibers, pair of them next to the nucleus.

Question 25

Role of centrioles?

Answer 25

Take part in cell division, form spindle fibers that move chromosomes during anaphase.

Question 26

Process of protein synthesis?

Answer 26

1. mRNA(contain genetic code)
2. Exits the nucleus, moving into the cytoplasm.
3. mRNA is translated, organised by the ribosomes
4. Assembled protein leaves the ribosome in a vesicle, where it may leave the cell or be used in the cell.

Question 27

What are the role of membranes?

Answer 27

• Separating cell contents from the outside environment
• Separate the cell components from cytoplasm
• Cell recognition and signalling
• Regulating the transport of materials into/out of the cell.

Question 28

Outline the structure of a phospholipid membrane.

Answer 28

• Hydrophilic head facing outwards.
• Hydrophobic tails facing inwards.
• Channel proteins allow quick movement of substances through the membrane
• Carrier proteins actively move substances across the membrane
• Glycoproteins/glycolipids:receptor sites.

Question 29

What is cell signalling?

Answer 29

The communication between cells using hormones and complimentary receptor site.

Question 30

What is diffusion?

Answer 30

Movement of molecules down a concentration gradient.

high conc. -> low conc.

Question 31

What is active transport?

Answer 31

Movement of molecules against its concentration gradient with the use of energy.

Question 32

What affects the rate of diffusion?

Answer 32

• Temperature
• Concentration gradient
• Distance
• Size of molecules
• Surface area

Question 33

Outline facilitated diffusion using channel proteins.

Answer 33

It is a passive process which allows the transport of ions through the cell surface membrane.

Question 34

Outline facilitated diffusion using carrier proteins.

Answer 34

It is a passive process which transports larger molecules through the cell surface membrane.

Question 35

Outline bulk transport.

Answer 35

• Endocytosis(into the cell)
• Exocytosis(out of the cell)
• Requires ATP

Question 36

Passive processes?

Answer 36

• Diffusion
• Facilitated diffusion
• Osmosis

Question 37

Active processes?

Answer 37

• Active transport

- Bulk transport

Question 38

What is osmosis?

Answer 38

Movement of water down its water potential gradient across a partially permeable membrane.

Question 39

What happens to animal cells in a solution with high water potential?

Answer 39

• Cell swells as water moves down the gradient and fills the cell
• Animal cell bursts as it does not have cell wall to withstand the pressure.

Question 40

What happens to plant cell in a solution with high water potential?

Answer 40

• Cell swells as water moves down the gradient and fills the cell
• Plant cell becomes turgid due to cell wall that prevents the cell from bursting

Question 41

What happens to animal cells in a solution with low water potential?

Answer 41

-Cell shrinks and membrane shrivels up.

Question 42

What happens to plant cell in a solution with low water potential?

Answer 42

-Cell shrinks and membrane will pull away from cell wall.

Question 43

Why do multi-cellular organisms need transport systems?

Answer 43

• Small SA/Vol ratio
• Not all cells in contact with external medium.
• Tissues, organs are created to allow delivery of oxygen and removal of carbon dioxide.

Question 44

What is differentiation?

Answer 44

When a cell takes on a particular role/function.

Question 45

How can cells adapt to become differentiated?

Answer 45

• Increase the number of certain organelles within the cell.

- Change the shape of the cell.

Question 46

What is tissue?

Answer 46

Collection of cells working together to perform a common function.

Question 47

What is organ?

Answer 47

Collection of tissues working together to perform a particular function.

Question 48

What is organ system?

Answer 48

Number of organs working together to perform an overall function.

Question 49

Outline the xylem tissue structure.

Answer 49

• Parenchyma cells and fibres
• Walls reinforced with lignin
• Sunken pits where lignin is absent to allow water molecules to move into live tissue cells around the xylem

Question 50

Outline the phloem tissue structure.

Answer 50

• Sieve tubes and companion cells.

- Companion cell is very metabolically active

Question 51

Give 2 examples of epithelial tissues.

Answer 51

• Squamous epithelial

- Ciliated epithelial

Question 52

Give 2 examples of connective tissues.

Answer 52

• Cartilage

- Bone & blood