B1

Question 1

what are the two types of cells?

Answer 1

-eukaryotic (plant/animal)
-prokaryotic (bacteria)

Question 2

what are the differences between prokaryotic and eukaryotic cells?

Answer 2

-prokaryotic cells are much smaller than eukaryotic
-eukaryotic cells contain a nucleus whilst prokaryotic do not

Question 3

what are plasmids?

Answer 3

small loops of DNA found in the cytoplasm

Question 4

Definition of a eukaryotic cell?

Answer 4

contain genetic material(DNA) in an enclosed nucleus

Question 5

Definition of a prokaryotic cell?

Answer 5

genetic material(DNA) is not stored in the nucleus

Question 6

how are sperm cells adapted to carry out their function?

Answer 6

-contain half genetic information
-long streamlined tail
-contain a lot of mitochondria

Question 7

how are root hair cells adapted to carry out their function?

Answer 7

-large surface area to increase rate of absorbsion
-do not contain chloroplast
-many mitochondria for energy

Question 8

how are xylem adapted to carry out their function?

Answer 8

-end walls are broken down forming a hollow tube,so no obstruction to water flow
- no nucleus cytoplasm ,vacuole, chloroplast
-has lignin

Question 9

how are phloem adapted to carry out their function?

Answer 9

-Made of living cells
-seive plates and companion cells
-seive plates contain pores so dissolved sugars can flow through
-companion cells contain alot of mitochondria for energy

Question 10

what is a stem cell?

Answer 10

-undifferentiated cell

Question 11

what does a stem cell do?

Answer 11

-give rise to more cells of the same type
-can differentiate to form other types of cells

Question 12

3 stages of mitosis

Answer 12

1- DNA replicates,two identical chromosomes
2- one set of chromosomes is pulled to each end of the cell,nucleus divides
3- cytoplasm and cell membrane divide forming two cells

Question 13

what is diffusion?

Answer 13

• the net movement of molecules from an area where they are at a higher concentration to areas where they are at a lower concentration.

Question 14

what is osmosis?

Answer 14

diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane

Question 15

what is active transport?

Answer 15

a process in which substances are moved from a more dilute solution to a more concentrated solution

Question 16

two types of microscopes?

Answer 16

-light magniscope
- electron microscope

Question 17

what is the benefit of electron microscope?

Answer 17

have much better magnification and resolution then light microscopes.

Question 18

magnification equation?

Answer 18

magnification=size of image/size of real object

Question 19

what is the function of the xylem

Answer 19

transporting water and dissolved minerals throughout the plant

Question 20

what is the function of root hair cells

Answer 20

-allows the plant to absorb more water.
-allow a plant to take in the minerals it needs to survive.

Question 21

what is the function of the phloem

Answer 21

moves food substances that the plant has produced by photosynthesis

Question 22

why is oil used in some experiments

Answer 22

to keep oxygen out

Question 23

what are advantages of using a persons stem cells

Answer 23

-no risk of damage to embryo
-adult can give consent
-know the side effects

Question 24

how is water transported from soil to the atmosphere

Answer 24

-absorbed from the soil by osmosis through root hair cells
-travels through xylem vessels through the leaves
-lost through the stomata to the atmosphere
-transpiration

Question 25

what is the stomata

Answer 25

Stomata are tiny openings or pores in plant tissue that allow for gas exchange.

Question 26

what is transpiration

Answer 26

the process of water constantly evaporating from the surface of the leaves

Question 27

what is the transpiration stream

Answer 27

-transpiration starts from the evaporation of water from cells inside the leaf -water vapour diffuses through air spaces in the spongy mesophyll and out of the leaf through the stomata -water passes into the leaf through the xylem to replace lost water -water is drawn into root hair cells and up the xylem vessels into the leaf

Question 28

why is transpiration important

Answer 28

-brings water into the leaf for photosynthesis -transports dissolved mineral ions,which play important roles in the plant -cools leaf down

Question 29

what factors effect transpiration

Answer 29

-temperature,evaporation is faster at higher temp -faster under dry conditions ,evaporation occurs quicker -faster in windy conditions due to removal of water vapour -high light intensity, higher rate of photosynthesis

Question 30

how do stomata’s work?

Answer 30

-surrounded by two guard cells -when light intensity is high,they swell and change shape this causes them to open -now carbon dioxide can enter the leaf and be used in photosynthesis

Question 31

what happens in the stomata in hot conditions

Answer 31

stomata closes to reduce water loss through transpiration, however this means the plant cannot photosynthesise

Question 32

what is Translocation

Answer 32

Translocation is the transport of dissolved sugars around a plant in the phloem

Question 33

how are sieve tube cells adapted for their function

Answer 33

-have small pores in end walls so dissolved sugars are able to move cell to cell

Question 34

why is it important that dissolved sugars move both upwards and downwards in a plant

Answer 34

-sugars are made in leaves by photosynthesis -all cells/tissues need sugars for respiration -sugars transported for storage as starch

Question 35

what is an independent variable

Answer 35

Independent variable – the variable that is altered during a scientific experiment.

Question 36

what is a control variable

Answer 36

a variable that is kept the same during a scientific experiment.

Question 37

what is a dependent variable

Answer 37

the variable being tested or measured during a scientific

Question 38

what are 4 differences between a plant and bacteria cell

Answer 38

-bacteria cell is smaller -bacteria cell does not contain chloroplast -bacteria does not contain DNA in an enclosed nucleus -Bacteria does not contain mitochondria

Question 39

when does respiration occur within plants

Answer 39

all the time

Question 40

why is peer review used

Answer 40

-to avoid bias -to prevent false claims -to make sure results are valid

Question 41

what is the use of mitochondria in cells

Answer 41

its where aerobic respiration takes place

Question 42

what makes up an animal cell

Answer 42

-nucleus -mitochondria -ribosomes -cell membrane -cytoplasm

Question 43

diffeences in plant an animal cells

Answer 43

-plant cells have a regular shape -chloroplast -cell wall -permanent vacuole

Question 44

what makes up a plant cell

Answer 44

-same as animal cell + -chloroplast -cell wall -permanent vacuole

Question 45

how is spongy mesophyll adapted for its function

Answer 45

-has large air spaces between cells -so gases can diffuse through the leaf from the paladside layer

Question 46

advantages of therapeutic cloning

Answer 46

-may cure or treat diseases -cells are unlikely to be rejected by patient -many cells are produced

Question 47

where are stem cells made

Answer 47

bone marrow

Question 48

what are disadvantages of therapeutic cloning

Answer 48

-potential life is killed -shortage of donors or eggs -poor success rate

Question 49

give one place in a plant where stem cells are found

Answer 49

meristem cells

Question 50

benefits of using embryonic stem cells

Answer 50

-can treat many diseases -less likely to be rejected

Question 51

negatives of using embryonic stem cells

Answer 51

-risk of embryo being destroyed -embryo cannot consent

Question 52

negatives of using adult stem cells

Answer 52

-may be rejected -only can treat a few diseases