cell biology

Question 1

diffusion

Answer 1

is the spreading out of particles from a main area of higher concentration to an area of lower concentration

Question 2

cell membranes

Answer 2

are semi permeable only small mollecules can get through

Question 3

osmosis

Answer 3

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

Question 4

active transport

Answer 4

is the movement of substances against concentration gradient. this process requires energery from respiration

Question 5

exchange in fish for gas exchange

Answer 5

fish have a large surface area for gas exchange called gills.
water enters fish through mouth and goes through gills.
oxygen is transported from the water to blood by diffusion.
carbon dioxide diffuses the blood to water.
gills have filaments which gives gills a larger surface area.
lamelle cover each gill to increase surface area.
they have thin surface layer and capilaries for good blood supply which helps diffusion

Question 6

multicellular

Answer 6

organisms that have large surface area to volume ratio so that all the substances can be exchanged.

Question 7

gass exchange in lungs

Answer 7

alveoli are where gas exchange takes place
large surface area ,moist lining, thin walls and good blood supply

Question 8

villi small intestines

Answer 8

millions of villi line the small intestines increasing the surface area to absorb more digested food.
single layer of cells with a good blood supply

Question 9

exchange in plants

Answer 9

surafce of leaf is flattened to increase surface area for more gas exchange by diffusion.
oxygen and water vapour diffuses out of the stomata. guard cells open and close the stomata, controlling water loss.

Question 10

stem cells embryonic

Answer 10

are undefined cells they have the potential to turn into any kind of cell

Question 11

adult stem cells

Answer 11

are found in bone marrow they can only turn into some types of cells e.g blood cells

Question 12

use of stem cells

Answer 12

replacing faulty blood cells
making insulin producing cells
making nerve cells

Question 13

positive of stem cell research

Answer 13

curing patients with stem cells- more important than the rights of embryos
they are using unwanted embryos from faternity clinics which would normally be destroyed so theirs no wastage.

Question 14

negative/against stem cell research

Answer 14

embryos are human life
scientists should find other sources of stem cells

Question 15

stem cells in plants

Answer 15

are found in the meristem these stem cells are able to produce clones of the plant. they can be used to grow crops with specific features for a farmer e.g disease resistant

Question 16

chromosomes

Answer 16

in the nucleus of a human cell there are 23 pairs of chromosomes containing double helix of DNA they have a large surface number of genes

Question 17

mitosis

Answer 17

the cell cycle makes new cells mitosis DNA has to be copied before the cell carries out mitosis

Question 18

what does a plant cell have that an animal cell doesn’t have

Answer 18

chloroplast, permeant vacuole , cell wall

Question 19

what does a plant cell contain of

Answer 19

nucleus, cytoplasm, chloroplast, cell membrane, permeant vacuole ,mitochondria, ribosomes ,cell wall

Question 20

what does an animal cell contain of

Answer 20

nucleus, cytoplasm, cell membrane, mitochondria, ribosomes,

Question 21

bacterial cells

Answer 21

do not have a true nucleus they just have a single strand of dnathat floats in the cytoplasm they contain a plasmid they are prokaryotic

Question 22

are plant and animals cells eukaryotic or prokaryotic

Answer 22

eukaryotic

Question 23

prokaryotic cells

Answer 23

small cells without a nucleus or membrane bound organells dna is in the cytoplasm
e.g bacteria and archaea

Question 24

eukaryotic cells

Answer 24

larger cells with a nucleus gna found in nucleus e.g plant and animal

Question 25

what does a bacteria cell contain

Answer 25

chromosome, cell wall, cell membrane, cytoplasm , flagella

Question 26

specialised cells

Answer 26

when a cell changeds to become a specialised cell it is called differentiation

Question 27

sperm function

Answer 27

to get male dna to female dna

Question 28

sperm adaptation

Answer 28

streamlined head, long tail, lots of mitochondria to provide energy

Question 29

nerve function

Answer 29

to send electrical impulses around the body

Question 30

nerve adaptation

Answer 30

long to cover more distance has branched conections to connect in a network

Question 31

muscle function

Answer 31

to contract quickly

Question 32

muscle adaptation

Answer 32

long and contain lots of mitochondria for energy

Question 33

root hair cell function

Answer 33

to absorb water from soil

Question 34

root hair adaptation

Answer 34

a large surface area to absorb more water

Question 35

phloem function

Answer 35

transports substances around the plant

Question 36

phloem adaptation

Answer 36

pores allow cell sap to flow cells are long and joined end- to- end

Question 37

xylem function

Answer 37

transports water throughout plant

Question 38

xylem adaptation

Answer 38

hollow in centre tubes are joined end to end

Question 39

osmosis potato practicle variables

Answer 39

independant- concentration dependant variables-change in mass control-temp,time