B1 Cells and Organisation

Question 1

What is cytoplasm?

Answer 1

a jelly-like fluid that fills the cell.

where most of the cell’s chemical reactions take place.

Question 2

(Bacterial cells)

What are flagella?

Answer 2

(only some bacteria have flagella)

they are whip-like structures used for movement

Question 3

(Bacterial cells)

What are plasmids?

Answer 3

Small rings of DNA.

Question 4

What type of cell are bacteria?

Answer 4

Prokaryotic

Question 5

Does Cell differentiation occur in mature animals? If so, why?

Answer 5

It does but rarely. It does do to replace cells and repair tissues.

Question 6

How are sperm cells specialised?

Answer 6

They have a ‘head’, an Acrosome (enzyme tip), Tail, and the ‘middle section’.

Question 7

What does the ‘head’ of the sperm cell contain?

Answer 7

The nucleus contains half of the genetic information.

This combines with the egg cell to fertilize it.

Question 8

What is an Acrosome?

Answer 8

The Acrosome contains enzymes needed for penetrating the egg cell.

Question 9

Where is the Acrosome?

Answer 9

At the tip of the head of a sperm cell.

Question 10

What is the ‘tail’ of a sperm cell? what does it do?

Answer 10

It is used for the cell’s motion. It allows the sperm to travel to the egg for fertilisation.

Question 11

How does the tail move?

Answer 11

The ‘middle section’ contains lots of mitochondria to provide the energy needed.

Question 12

What is the ‘middle section’ of a sperm cell?

Answer 12

It is the part filled with mitochondia to provide the cell with energy for movement.

Question 13

What is cell differentiation?

Answer 13

When a cell gains new sub- cellular structures in order to perform a specific function. When this happens the cell becomes ‘specialised’

Question 14

How do sperm cells move their tail?

Answer 14

In a corkscrew motion

Question 15

What are mitochondria?

Answer 15

Respire aerobically to release energy in the cell.

Question 16

What is an enzyme?

Answer 16

Enzymes are ‘biological catalysts’. They speed up the rate of chemical reactions without being used up themselves.

Question 17

What kind of signals do nerve cells transmit?

Answer 17

Electrical

Question 18

How big are eukaryotic cells?

Answer 18

10 - 100 µm (micrometer)

Question 19

What do ALL eukaryotic cells contain?

Answer 19

All eukaryotic cells contain a cell membrane, cytoplasm and a nucleus.

Question 20

Do Prokaryotic cells contain nuclei?

Answer 20

Prokaryotic cells do NOT have a nucleus. Instead, their genetic material is stored in a single DNA loop in the cytoplasm.

Question 21

Examples of eukaryotic cells are..?

Answer 21

Plants, animals, fungi, protists

Question 22

Examples of prokaryotic cells:

Answer 22

Bacteria

Question 23

How big are prokaryotic cells?

Answer 23

0.1 - 5.0 µm

Question 24

What do ribosomes do?

Answer 24

They are responsible for synthesising (making) proteins.

Question 25

What is a Permanent vacuole?

Answer 25

it is a fluid-filled sac which takes up 90% of a cell's volume. it has a partially permeable membrane.

Question 26

What does a permanent vacuole do?

Answer 26

Gives support and structure to a cell.

Question 27

What is a chloroplast?

Answer 27

They contain chlorophyll, which is used in photosynthesis.

Question 28

What is a cell wall? What does it do?

Answer 28

The cell wall surrounds the cell. It increases the structural strength of the cell.

Question 29

What is the cell wall made of?

Answer 29

Made of cellulose.

Question 30

When does cell differentiation occur?

Answer 30

When a cell aquires different sub-cellular structures.

Question 31

What does an animal cell contain? (5 things)

Answer 31

Cytoplasm, cell membrane, nucleus, ribosomes, mitochondria

Question 32

What does a permanent vacuole store?

Answer 32

They store sap.

Question 33

What is the nucleus and what does it do?

Answer 33

The control centre of the cell, which contains the genetic material, in the form of chromosomes.

Question 34

What is the cell membrane and what does it do?

Answer 34

Separates the interior of the cell from the environment outside. It is selectively permeable (it can control substances moving in and out of the cell).

Question 35

What is the resolving power in a microscope? [1]

Answer 35

Resolving power is the smallest size that a microscope can show.

Question 36

What is photosynthesis? [1] | what does it do? [1]

Answer 36

- Photosynthesis is the reaction plants use to make glucose | - Glucose is used in respiration, growth and repair in plants.

Question 37

What are examples of specialised animal cells? | How are they specialised? [3]

Answer 37

1) Sperm - has a tail to move. 2) Nerve - carries electrical impulses 3) Muscle - can contract and relax

Question 38

What are examples of specialised plant cells? | How are they specialised? [3]

Answer 38

1) Root hair - Absorbs water and mineral ions 2) Xylem - carries water and minerals 3) Phloem - carries glucose to cells

Question 39

What does a plant cell contain? (8 things)

Answer 39

Mitochondria, Cell membrane, ribosomes, nucleus, cytoplasm, vacuole, cell wall, chloroplasts

Question 40

What do Xylem cells transport?

Answer 40

Water and mineral ions

Question 41

What do phloem cells transport?

Answer 41

'food' (glucose) made by photosynthesis

Question 42

What direction do xylem cells transport substances?

Answer 42

From root to shoot. Only ONE direction.

Question 43

Other than transporting substances, why are xylem cells important? How do they do this?

Answer 43

They give the plant structure - they are alive when first formed but a chemical called 'lignin' builds up in cell walls. The cells die and form long, hollow tubes that allow water and mineral ions to be transported.

Question 44

What makes xylem cells strong?

Answer 44

Spirals of lignin in xylem cell walls make them very strong.

Question 45

How are phloem cells specialised?

Answer 45

They are tube-like, but have holes in their end walls for cytoplasm (goo where reactions happen) to move through and transport glucose and plant food.

Question 46

How are phloem cells supported?

Answer 46

They have 'companion cells', whose mitochondria transfer energy for the food to move.

Question 47

what direction does phloem take substances?

Answer 47

Phoem takes substances BOTH up and down the plant, to areas of growth and/or repair.

Question 48

What are the three types of transport in cells?

Answer 48

Diffusion, Osmosis and Active transport

Question 49

What does diffusion transfer?

Answer 49

It is the movement of gas or dissolved minerals.

Question 50

True or false: Diffusion goes against a concentration gradient

Answer 50

FALSE. Diffusion goes DOWN a concentration gradient. (Imagine it's like a slide)

Question 51

What direction does diffusion take a substance?

Answer 51

High concentration ---> Low concentration

Question 52

Name three things that can affect the rate (speed of) diffusion.

Answer 52

- Difference in concentrations - Temperature - Surface Area

Question 53

Where does diffusion happen in the body?

Answer 53

``` In cells (across cell membrane) In lungs (oxygen into and carbon dioxide out of Red Blood cells) ```

Question 54

Osmosis is the net (overall) movement of...

Answer 54

Water (ONLY)

Question 55

does a dilute solution have a high concentration of water or a low concentration?

Answer 55

``` Dilute = high conc. (of water - low conc. of solute) concentrated = low conc of water ```

Question 56

How is osmosis different?

Answer 56

It moves through a partially permeable membrane. These only allow some types of subtance to get through

Question 57

define Isotonic

Answer 57

when the concentration of solutes (dissolved substance) is the same IN the cell as it is OUTSIDE the cell.

Question 58

Define Hypertonic (NOT HYPOtonic)

Answer 58

The concentration of solutes outside is HIGHER than inside.

Question 59

Define Hypotonic (NOT HYPERtonic)

Answer 59

The concentration of solutes outside is LOWER than inside.

Question 60

Why is osmosis important in body cells?

Answer 60

It maintains the pressure inside the cell, which is called turgor.

Question 61

True or false- active transport does not require energy

Answer 61

False - unlike Osmosis and diffusion, Active Transport needs energy. Osmosis and diffusion are PASSIVE, active transport is ACTIVE

Question 62

What direction does active transport go?

Answer 62

Low Concentration ---> High concentration. | AGAINST a concentration gradient

Question 63

What does active transport move?

Answer 63

Mineral ions (eg. magnesium or nitrates)

Question 64

How is the Surface area : volume ratio important?

Answer 64

It affects the rate of reaction.

Question 65

What are exchange surfaces?

Answer 65

They usually have a large surface area and thin walls, to maximise efficiency across surfaces.