Chapter 1 - Cell structure and transport

Question 1

What is the formula to calculate magnification?

Answer 1

magnification=image size/real size

Question 2

How long is an average animal cell?

Answer 2

10-30 micrometres

Question 3

What is the function of the nucleus?

Answer 3

controls all the activities of the cell and contains the genes

Question 4

What is the cytoplasm and what does it do?

Answer 4

a liquid gel where chemical processes take place

Question 5

What is the function of the cell membrane?

Answer 5

holds the cell together and controls what goes in and out of the cell

Question 6

What is the function of mitochondria?

Answer 6

where most of the reactions for aerobic respiration take place

Question 7

What is the function of ribosomes?

Answer 7

where proteins are made

Question 8

What parts do plant cells have that animal cells don’t?

Answer 8

cell wall, vacuole, chloroplasts

Question 9

What is the function of the cell wall?

Answer 9

made of cellulose, supports the cell and strengthens it

Question 10

What is the vacuole?

Answer 10

contains cell sap, a weak solution of sugar and salts

Question 11

What is the function of chloroplasts?

Answer 11

where photosynthesis takes place, it contains a green substance called chlorophyll

Question 12

what is the function of chlorophyll?

Answer 12

absorbs light needed for photosynthese

Question 13

What other types of cells also have a cell wall and chloroplasts?

Answer 13

algae (eg: seaweed)

Question 14

What are eukaryotic cells?

Answer 14

eukaryotic cells have a cell membrane, cytoplasm and genetic material that is in a nucleus.

Question 15

What are prokaryotic cells?

Answer 15

prokaryotic cells have a cell membrane and cytoplasm that is surrounded by a cell wall, but the cell wall is not made of cellulose. the genetic material is not in a nucleus, they have a single circular strand of DNA which floats freely in the cytoplasm

Question 16

What are plasmids?

Answer 16

small rings of DNA

Question 17

What are some examples of eukaryotes?

Answer 17

plants, fungi and protista

Question 18

What is a feature of plasmids?

Answer 18

antibiotic resistance

Question 19

What is flagella and what is their function?

Answer 19

a long protein strand that lashes about and the bacteria uses them to move around

Question 20

What parts do bacteria cells have?

Answer 20

cytoplasm, cell membrane, cell wall, plasmids and some have flagella

Question 21

What allows cells to carry out specific functions?

Answer 21

• developing different sub cellular structures

- turning into different types of cells

Question 22

What happens to animal cells’ ability to differentiate?

Answer 22

it’s lost at an early stage

Question 23

What happens to plant cells’ ability to differentiate?

Answer 23

it isn’t ever lost

Question 24

What are the cells that differentiate in mature animals mainly used for?

Answer 24

repairing and replacing cells such as skin or blood cells

Question 25

What are stem cells?

Answer 25

undifferentiated cells

Question 26

What are sperm cells specialized for?

Answer 26

reproduction

Question 27

What is the function of sperm cells?

Answer 27

to get the male DNA to the female DNA

Question 28

What are 3 adaptations of sperm cells?

Answer 28

have a long tail and streamlined head to help swim, has lots of mitochondria to provide energy, carries enzymes in its head to digest through the egg cell membrane

Question 29

What is the relative size of eukaryotic cells?

Answer 29

10-100 micrometres

Question 30

what is the relative size of prokaryotic cells?

Answer 30

1-3 micrometres

Question 31

How do you calculate orders of magnitude?

Answer 31

if bigger no./smaller no. is less than 10, then they have the same order of magnitude. if bigger no./smaller no. is around 10, then the OofM is 10^1 bigger. if bigger no./smaller no. is around 100, then the OofM is 10^2 bigger

Question 32

What are nerve cells specialised for?

Answer 32

rapid signalling

Question 33

What is the function of nerve cells?

Answer 33

to carry electrical signals from one part of the body to another.

Question 34

What are 2 adaptations of nerve cells?

Answer 34

they are long so they cover more distance, have branched connections to connect to other nerve cells and form a network throughout the body

Question 35

What are muscle cells adapted for?

Answer 35

contraction

Question 36

What is the function of muscle cells?

Answer 36

to contract quickly

Question 37

What are 2 adaptations of muscle cells?

Answer 37

- long so they have space to contract | - contain lots of mitochondria to make energy for the contraction

Question 38

What are root hair cells specialised for?

Answer 38

absorbing water and minerals

Question 39

What are root hair cells?

Answer 39

cells on the surface of plant roots, which grow into long "hairs" that stick out into the soil

Question 40

What is an adaptation of root hair cells?

Answer 40

-long, gives the plant a big surface area for absorbing water and minerals

Question 41

What are phloem and xylem cells specialised for?

Answer 41

transporting substances

Question 42

What is the function of phloem and xylem cells?

Answer 42

form phloem and xylem tubes which transport substances, such as food and water, around plants

Question 43

What are 3 adaptations of phloem and xylem? (1 both, 1 xylem, 1 phloem)

Answer 43

both are long and joined end to end, xylem and hollow in the centre, phloem have very few subcellular structures so that stuff can flow through them

Question 44

What is diffusion?

Answer 44

the spreading out of particles from an area of high concentration to an area of low concentration.

Question 45

What states of matter does diffusion occur in and why?

Answer 45

liquids and gasses because the particles are free to move around

Question 46

When is the diffusion rate faster?

Answer 46

when there is a higher concentration gradient and a higher temperature because the particles have more energy= move around faster

Question 47

What can move in and out by diffusion?

Answer 47

dissolved substances

Question 48

What type of molecules can diffuse through cell membranes? examples?

Answer 48

very small molecules, like: oxygen, glucose, amino acids & water

Question 49

What is osmosis?

Answer 49

the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

Question 50

What is a partially permeable membrane?

Answer 50

a membrane with very small holes in it

Question 51

Which way do the water molecules pass in osmosis? why?

Answer 51

both ways because water molecules move about randomly

Question 52

How does osmosis work in plants?

Answer 52

- water moves into the plant - causes the vacuole to swell - presses the cytoplasm against the plant cell wall - pressure (-TURGOR) builds up until no more water can enter - turgor makes the cell hard and rigid and leaves and stems are firm

Question 53

What is plasmolysis?

Answer 53

when more water is lost by osmosis, in plants, so the vacuole and cytoplasm shrink and eventually the cell membrane pulls away from the cell wall

Question 54

Why can't root hair cells use diffusion to take up minerals from the soil?

Answer 54

the concentration of minerals is usually higher in the root hair cells than in the soil around them

Question 55

What is active transport?

Answer 55

the plant absorbs minerals from a very dilute solution, against a very concentrated gradient

Question 56

When is active transport used in the human gut?

Answer 56

when there is a lower concentration of nutrients in the gut, but a higher concentration of nutrients in the blood

Question 57

The larger an organism is, the _____ its surface area is compared to its volume

Answer 57

smaller

Question 58

What are 2 adaptations of exchange surfaces?

Answer 58

- thin membrane = substances have a short distance to diffuse - large surface area = lots of substances can diffuse at once

Question 59

single-celled organisms have a relatively ____ surface area to volume ratio so all the exchanges happen ____

Answer 59

large, here

Question 60

multi cellular organisms have a _____ surface area compared to their volume so __ _____ substances can diffuse from their outside surface to supply their entire volume. so they need an ______ _______

Answer 60

smaller, not enough, exchange surface

Question 61

What are 2 adaptations on exchange surfaces in animals?

Answer 61

- have an efficient blood supply = get stuff in and out of the body quickly - gas exchange surfaces are ventilates = air move in and out