Depth paper notes

Question 1

Ways the images produced by LSCM and Electron microscope differ

Answer 1

LCSM: lower resolution, fluorescent tags, can see movement of living cells

Question 2

Xylem and phloem similarity

Answer 2

Both xylem and phloem are made up of cells joined end to end

Question 3

Differences between xylem and phloem

Answer 3

Xylem = lignified cell walls, no sieve plates
Phloem = non-lignified cell walls, has sieve plates

Question 4

Dissection of bony fish

Answer 4

Dissection of bony fish:
-Removal of operculum
-Dissect underwater, place rod in buccal cavity to display lamallae, stain tracheoles with methylene blue

Question 5

Insect dissection

Answer 5

Dissecting insects:
-Removal of exoskeleton

Question 6

Difference of treacheae of insect and of mammal

Answer 6

Insect trachea = multiple tracheae, smaller diameter, made up of chitin, spiral support, shorter, branches into tracheoles
Mammal trachea = one trachea, alrger diameter, c-shaped cartilage rings, larger, branches into bronchi

Question 7

Alveoli adaptations for efficient gas exchange

Answer 7

Alveoli adaptations for efficient gas exchange:
-Large sa:vol ratio for increased diffusion rate
-Thin walls that are once cell thick for shorter diffusion pathway
-Good blood supply ->maintains a concentration gradient
-Well ventilated -> oxygen constantly being replenished and co2 constantly removed
-Elastic fibres - strretch and recoil
stretch -> increases surface area
recoil -> helps force air out

Question 8

How callibration curves are used to estimate glucose concentration

Answer 8

How callibration curves are used to estimate glucose concentration:
-Find absorbance using colorimeter
-Find concentration that corresponds to the absorbance on the callbration curve on graph

Question 9

Two similarities of cholesterol and glucose molecular structure

Answer 9

Both cholesterol and glucose contain C and H atoms, and has OH groups

Question 10

Physical property of glucose that allows it to be transported in the blood stream

Answer 10

Physical property of glucose that allows it to be transported in the blood stream: glucose is soluble in water

Question 11

Cell found in phloem that contains sap

Answer 11

The sieve tube cell in the phloem contains the sap

Question 12

Why can starch not be transported in sap?

Answer 12

Starch cannot be transported in sap because it is insoluble

Question 13

Importance of differential staining

Answer 13

Importance of differential staining:
-Different organelles can be seen
-Different cells can be seen
-Allows for contrasting
-Allows white blood cells (with are otherwise transparent/colourless)

Question 14

Difference of characteristics within a population

Answer 14

Intraspecific variation

Question 15

Potometer precautions for setting up and during the procedure

Answer 15

Potometer:
-Ensure it is watertight/airtight
-So no bubbles enter
-Cut stem underwater
-Use apparatus under water
-Use syringe to move bubble -> doesn’t move too far/doesn’t enter xylem/same bubble can be re-used

Question 16

Reasons for anomolies

Answer 16

Anomolies:
-Misread scale
-Times for longer
-External condiitons eg temp increase

Question 17

Why is capillary tube useful in measuring transpiration?

Answer 17

Capillary tube is useful in measuring transpiration because:
-Small diameter -> distance is greater/easier to measure

Question 18

Disaccharide examples

Answer 18

-Starch -> disacharide + non reducing sugar
-Lactose + Malstone -> disacharides + reducing sugars

Question 19

Testing for haemoglobin

Answer 19

Testing for haemoglobin:
-Biuret reagent
-Colour change (blue -> purple)
-Compare with a control

Question 20

Measuring glucose concentration without a colorimeter

Answer 20

Measuring glucose concentration without a colorimeter:
-Benedicts strips or biosensor
-Observe colour change

Question 21

Biosensors

Answer 21

Biosensors analyse concentrations of substances within solutions eg glucose

Question 22

How to callibrate a colorimeter before measuring glucose concentration

Answer 22

Callibrating a colorimeter:
-Red filter use
-Use known concentration
-Serial dilution
-Cuvette used with transparent slides
-Use of distilled water -> sets it to zero

Question 23

Cilliated epithelial cells locations

Answer 23

Cilliated epithelial cells locations:
-Trachea
-Bronchi
-Bronchioles
-Lungs

Question 24

Investigating cell membrane permeability -> effect of temperature on beetroot membranes

Answer 24

Effect of temperature on beetroot membranes:
1). cut 5 equal sizes and rinse to remove excess pigment released whilst cutting
2). add 5cm^3 of water to each
3). Use of water baths with varying temperatures and use stopwatch
4) carry out colorimetry
5). higher the permeability -> more pigment release -> higher absorbance

Question 25

Control variables of beetroot membrane permeability practical

Answer 25

Control variables of beetroot membrane permeability practical:
-Mass/length of beetroot
-Beetroot species all the same
-Same volumes of water

Question 26

Neutriphil specialisations

Answer 26

Neutriphil specialisations:
-Multilobed nucleus allows them to move and engulf material more easily
-Many lysosomes
-Immune response
-Engulfs pathogens

Question 27

Sperm cells specialisations

Answer 27

Sperm cells specialisations:
-Specialised lysosome called acrosome, contains digestive enzymes to enter egg cell

Question 28

Squamous epithelial cells

Answer 28

Squamous epithelial cells specialisations:
-thin and flat, reduces diffusion distance
-Tightly packed
-For rapid diffusion

Question 29

Palisade cells specialisations

Answer 29

Palisade cells specialisations:
-Lots of chloroplasts, long and cylindrical allowing close packing, chloroplast can be moved by cytoskeleton to maximise light absorption

Question 30

Guard cells specialisation

Answer 30

Guard cells specialisation:
-Contrls opening and closing of stomata -> ATP used to pump potassium ions into cells to make water move in by osmosis to open the stomata

Question 31

Order of increasing size of stem cells

Answer 31

Order of increasing size of stem cells:
Totipotent -> pluripotent -> multipotent -> unipotent

Question 32

Cilliated epithelial cells specialisations

Answer 32

Cilliated epithelial cells specialisations:
-Cillia -> wafts mucus -> to be ingestion (pathogens)
-Moves ovum/egg from ovary to uterus (site of fertilisation)