B.2 Scaling Up

Question 1

What is diffusion?

Answer 1

Net movement of particles from a higher to lower concentration

Question 2

Do the particles move up or down a concentration gradient (diffusion)?

Answer 2

Down

Question 3

What is an example of diffusion in the human body?

Answer 3

Glucose and oxygen diffusing into cells

Question 4

What factors affect rate of diffusion?

Answer 4

Distance for particles to move
Surface Area
Increase concentration gradient

Question 5

What is concentration gradient?

Answer 5

A concentration gradient exists when there is a region of high concentration leading to a region of low concentration

Question 6

What is osmosis?

Answer 6

The diffusion of water molecules across a semi permeable membrane from a higher water potential to a lower one

Question 7

What is water potential?

Answer 7

Concentration of free water molecules

Question 8

What is active transport?

Answer 8

Allows cells to move substances from an area of low concentration to an area of high concentration. As particles are moving against their concentration gradient, energy has to be transferred from an energy store (ATP from respiration)

Question 9

What do cells which carry out a lot of active transport contain?

Answer 9

Lots of mitochondria

Question 10

What does mitochondria allow them to do?

Answer 10

Respire rapidly to produce larger amounts of ATP

Question 11

Active transports rate depends on…?

Answer 11

Rate of respiration to produce ATP

Question 12

What are carrier proteins?

Answer 12

Special protein that stretch across width of cell membrane.
Molecules bind to the protein and the protein uses ATP to release the molecule inside the cell

Question 13

What is an animal example of active transport?

Answer 13

During digestion.
Small intestine carbohydrates are broken into glucose. Glucose in actively transported into the bloodstream through villi

Question 14

What is a plant example of active transport?

Answer 14

Taking minerals from the soil, root hair cell moves nitrate ions across cell membrane and into root cell

Question 15

What is the size order for:
DNA, chromosone, gene , nucleotide

Answer 15

nucleotide
Gene
DNA
Chromosone

Question 16

What is mitosis?

Answer 16

Body cells divide into two identical daughter cells.

Question 17

Why is mitosis used?

Answer 17

To replace and repair and asexual reproduction

Question 18

What are the four stages of the cell cycle?

Answer 18

DNA replication
Movement of chromosomes
Cytokinesis
Growth of daughter cells

Question 19

What is cytokinesis?

Answer 19

Cytoplasm dividing

Question 20

How do the chromosomes move?

Answer 20

They line up along the middle and because they have been replicated, copies of each pull to either end of the cell

Question 21

What does differentiation mean?

Answer 21

Specialised for a specific job, its structure changes so it is better adapted to perform its function

Question 22

Name 3 examples of cells which have become specialised

Answer 22

Sperm
Fat
Red blood cell

Question 23

How has the sperm cell been specialised?

Answer 23

A flagellum so it can swim
Lots of mitochondria for energy
Acrosome, break down outer layer of ovum

Question 24

How had the fat cell been specialised

Answer 24

Specialised to store fat, can expand massively

Question 25

Why else are fat cells good?

Answer 25

Insulation and protective

Question 26

How has a red blood cell been adapted?

Answer 26

Biconcave disks - increase surface area , speeds up diffusion Full of haemoglobin No nucleus so there is more space for haemoglobin

Question 27

Name a plant cell which has been adapted?

Answer 27

Palisade cell

Question 28

How is the palisade cell specialised?

Answer 28

For photosynthesis. Near surface of leaf, packed full of chloroplast

Question 29

What are stem cells?

Answer 29

Cells which can divide into any type of specialised cell

Question 30

What are the two types of stem cells?

Answer 30

Adult stem and embryonic

Question 31

What is the difference between embryonic stem cells and adult stem cells?

Answer 31

Embryonic can differentiate into any cell Adult stem cells can only dive into various body cells

Question 32

Where are stem cells found in plants?

Answer 32

Meristems

Question 33

Explain gaseous exchange?

Answer 33

Capillaries have a high concentration of carbon dioxide and a low concentration of oxygen, alveoli as the opposite so both move from their higher to lower concentration by diffusion

Question 34

What transports deoxygenated blood to the lungs?

Answer 34

Pulmonary artery

Question 35

What transports oxygenated blood back to heart from lungs?

Answer 35

Pulmonary vein

Question 36

What transports oxygenated blood from heart to body?

Answer 36

Aorta

Question 37

What transports deoxygenated blood back to body?

Answer 37

Vena cava

Question 38

What are the differences between a capillary, artery and vein?

Answer 38

Artery - Tick outer layer, small lumen Capillary - Very small lumen, wall made out of singe layer of cells Vein - Big lumen and thin walls

Question 39

What does the xylem do?

Answer 39

Transports water and mineral ions from roots to stem ( upwards motion ) Transpiration

Question 40

What does the phloem do?

Answer 40

transports dissolved sugars all around the plant. Translocation

Question 41

What is the structure of the xylem?

Answer 41

Xylem vessels are made from dead xylem cells, no cell walls

Question 42

What is the structure of the phloem?

Answer 42

Made of living cells. They have sieve plates which have small holes

Question 43

How does water enter the xylem?

Answer 43

Water diffuses from the soil into root hair cells by osmosis

Question 44

How is water lost from leaves?

Answer 44

The stomata on the surface of leaves. Uses guard cells to allow the stomata to open and close. When open, water vapour diffuses out

Question 45

What is plant wilt?

Answer 45

When the plant loses water faster than it takes it in

Question 46

What factors affect the rate of transpiration?

Answer 46

Light intensity Temperature Air movement Humidity