Mistakes Flashcards
(101 cards)
1
Q
What is the approximate width of a membrane
A
7um
2
Q
Colour change in buret test
A
blue to lilic purple
3
Q
Bind between two sugars
A
glycosdic
4
Q
Describe a test that the student could carry out to discover whether this sample contained a lipid.
A
Add mix with ethanol, , then add water
5
Q
Difference in structure of triglyercide and phospholipid
A
P-lipids - 2 fatty acids - P replaces one of the fatty acids 2 ester bonds not 3 polar/hydrophilic head
6
Q
Describe how malonate inhibits the enzyme. You may use the space below for a diagram to help your answer.
(in isn’t permanent)
A
similar shape to substrate inhibitor complementary to active site blocks active site for limite dite / reversible prevents es complex forming no products formed
7
Q
Explain what would happen to the reaction if the concentration of succinate was increased relative to the concentration of malonate.
A
greater chance of substrate binding with site
more es substrates- products
reaction rate increases
8
Q
Use the diagram to explain why this drug is effective in the treatment of gout.
(diagram of drug and substrate that are similar )
A
similar shape to drug –> drug fits active site –>competes-competitive inhibitor
less acid formed
9
Q
Cells under ciliated epithelium in bronchiole
A
smooth muscle (look like flat eyes)
10
Q
Blobs in oesophagus
A
Blood vessel (bRANCHED)
11
Q
What is function of ciliated epithelium
A
cilia beat, mucus moved back up bronchiole, protective
12
Q
one similarity between hair like structure in intestine and ciliated epithelial
A
Both columnar epithelial
13
Q
one Difference between hair like structure in intestine and ciliated epithelial
A
microvilli vs cilia
14
Q
Glycosidic bonds between what and what is removed
A
monosachride molecules and water
15
Q
Colour change in benefits solution
A
blue to red brown preicipate
16
Q
how can bond be broken chemically to break apart a non reducing sugar
A
hydrolyse by heating ( dilute HCL)
17
Q
Explain how structure of stomach walls and oesophagus wall are related to the functions oft these organs
A
oesophagus - Thick mucusa /epithelial layer, outer cells flatted
- withstands abrasion from semi solid food
oesophagus food from mouth to stomach
stomach = site of digestion - protein
food churned with acid and endopeptidases
thick mucose / gastric pits = gastric juices
mucus secretion - protection
muscular wall = 3 layers muscles - churn and break up food
18
Q
describe the function of the up going up in ileum
A
Absorbs/ transports triglycerides
19
Q
Advantage of having muscle in villi
A
allow movement of villi - greater contact with food in lumen for digestion /absorption
20
Q
How is the inner membrane of the mitochondria adapted to its function
A
inner membrane (folded)
increases surface area to form cristae
mitochondria site of respiration /ATP production
greater SA - greater ATP production
21
Q
Comparison of prokaryotic and eukaryotic
A
Ribosomes present : yes yes
cell diameter usually more than 20 um = eu= yes , pro= no
cells may contain plasmid- pro = yes, eu - no
dna combined with protein into chromosomes - pro -= yes , eu = yes
nuclear membrane present - pro - no, eu - yes
cell wall always present , pro - yes , eu - no
22
Q
Using the information given above, suggest why the COX enzyme is found attached to the inner surface of the endoplasmic reticulum.
A
idea th
at arachindate is substrate
p lipid source in membrane
SER for lipid/steroid synth?/transport
prostaglandins can be transported /stored
AVP- separate from other cellular reactions
prostaglandins isolated in ER
P lipids from other membranes unaffected
23
Q
Describe the effect of low temperature ,such as 5 oc , on enzyme action
A
Decrease reaction rate ref. kinetic energy molecules moving more slowly fewer collisions fewer es complexes reversibel - Enzyme not dnatured
24
Q
How many something be kept as a control
A
contains all substances except one
25
projections on CELL
microvilli
26
correct term for outer layer
EPethITHIAL LAYER
27
(ii) Explain how transport of sugars into cells lining the intestine (lines 8-9) leads to water being absorbed.
sugar absorbed, fluid in gut becomes less negative than that of blood, water passes into blood by osmosis
28
Plasma membranes that have been isolated from red blood cells are not contaminated by internal cell membranes.
Explain why.
no internal membrane bound organelles
29
Explain why red blood cells that do not contain spectrin burst more quickly when put into distilled water.
spectrum strengthens the membrane, cells swell when place in distilled water (osmosis) - weaker membrane rupture more easily
30
Suggest what caused the sudden increase in the rate of diffusion at 40 °C.
break down of bonding in membrane, (due to kinetic energy ), proteins denature
31
Describe the function of ribosomes
site of protein synthesis
| where genetic code is used to build protein
32
Describe the function of lysosomes
protein digestion (enzyme )
digest warn out organelles
in white blood cells- phagocytosis
digest cell when dies
33
Describe the function of nuclear pres
to allow substances into and out of cell
| connects nucleus to cytoplasm via MRNA
34
Explain why the change in mass was given as a percentage change.
allows accurate comparison
| graph accuracy
35
what is the point called where there is no change in mass ( due to concentration of something )
isotonic point
36
Use your knowledge of enzymes to explain how cyanide stops the activity of cytochrome oxidase.
binds to enzyme at point away from the active site
changes 3 o structure
alters active site
so ES complex can't for m
37
Suggest what type of substance would cause the antibody to attach only to cancer cells.
protein
38
Explain how this method would kill cancer cells, but not other cells.
antibody only bids to receptor protein on cancer cells
antibody has enzyme attached
linemen injected will only be broken down at cancer cell sites
cynaide released to cancer cells
39
With reference to Fig. 2.1, describe the events occurring at the stages labelled 1 to 4. (order to events for secretion of insulin )
glucose , respired / phosphorylated / metabolised ,
to produce ATP ;
2 ATP , blocks / closes , potassium ion channel(s) and
potassium ions / K+ ,
build up (inside cell) / cannot leave ;
3 (voltage-gated) calcium ion / Ca2+ , channels open and
calcium ions / Ca2+ , enter (cell by diffusion) ;
4 (more) calcium ions / Ca2+ , resulting in , movement of vesicles to membrane /
exocytosis / described ;
40
After the initial release of insulin from the beta cell, insulin secretion continues even when there is no further glucose intake.
Suggest and explain why the cell continues to secrete insulin.
1 (continues to be secreted) as long as
blood / plasma , glucose (concentration) ,
remains high / is higher than normal ;
2 (sufficient) ATP is still present
and so K+ channels remain closed ;
3 (exocytosis) still being triggered by ,
calcium ions / Ca2+;
41
Where do these occur
link reaction
glycolysis
electron transport chain Krebs cycl
link reaction -matrix
glycolysis - outside mitconhdria in cytoplasm
electron transport chain - on inner membrane
Krebs cycle - matrix
42
Describe how glucagon is involved in the regulation of blood glucose concentration in a person who is able to regulate their blood glucose concentration correctly.
when blood glucose concentration decreases
1 (glucagon) released by the , alpha / , cells in , islets of Langerhans / pancreas ;
2 promotes / AW ,
conversion of glycogen to glucose /
glycogenolysis ,
in , liver / muscle / effector , cells ;
3 ref gluconeogenesis / described ;
4 ref conversion of triglycerides to (free) fatty acids / lipolysis /
increased use of fatty acids in respiration ;
5 negative feedback ,
reduces / inhibits , the secretion of glucagon ;
6 glucagon , reduces / inhibits , insulin secretion ;
43
LABEL LIVER PART
```
A sinusoid ;
B (branch of) bile duct ;
C (branch of) hepatic portal vein ;
D (branch of) hepatic artery / arteriole ;
E (branch of) hepatic / central , vein ;
```
44
The liver has considerable powers of regeneration, even if a high proportion of its cells are damaged.
Name the liver cells that can lead to this regeneration and the type of cell division that they carry out.
hepatocytes
| MITOSIS
45
Steroid hormones are not made of protein. They are classed as lipids. Their structure means that they can diffuse through the cell surface and nuclear membranes. The hormones then bind to DNA in the nucleus and switch genes on and off.
Explain why steroid hormones can diffuse through cell membranes.
fat soluble / non-polar / uncharged / hydrophobic ; (so can move directly through) phospholipid bilayer ;
46
(ii) Describe the structure of the collagen molecule.
peptide bonds , between amino acids / in polypeptide
every 3rd amino acids is , same / glycine ;
coil / twist / spiral / helix ;
left-handed (helix) ;]
glycine / small R group , allows closeness /
three polypeptide chains ;
hydrogen / H , bonds between (polypeptide)
no / few, hydrophilic (R) groups on outside (of molecule) ;
(adjacent molecules joined by) crosslinks ;
crosslinks / ends of molecules , being staggered
fibril ;
47
Describe three other ways in which the structure of haemoglobin differs from that of collagen.
globular
hydrophobic (R) groups on inside / hydrophilic
3 4 , chains / sub-units / polypeptides ;
4 idea that subunits are (two) different types ;
5 α/alpha,helix;
idea that proportion of glycine similar to that , of other amino acids / in other proteins ;
48
Explain how phagocytes, such as those shown in Fig. 3.1, are able to pass from the blood into the tissue fluid.
1. lobed / narrow , nucleus ;
2 (cells) can change shape ;
2
3 can squeeze / move / fit / AW , between cells / through pores , in (walls of) capillaries ;
4 histamine makes , capillary walls / endothelium , leaky ;
49
(a) State two functions of membranes within cells.
orms, vesicles / (named) organelle(s) ;
Guidance ACCEPT transport in vesicles
separate (contents of) organelles from cytoplasm / compartmentalisation ;
te of (named), processes / reactions ;
provides surface for attachment (of enzymes / ribosomes) ; control what substances, enter / leave, organelles ;
AVP ;
50
WHEN SUGGESTING AN EXPERIMENT what should you remember:
- controls of ph , temperate,
- replication s
- control with none of thing testing
51
Proteins are required in large amounts in the diet whereas vitamins and minerals are required only in small amounts.
Suggest why.
idea of cofactors / minerals being , recycled / used again
dea that in enzyme action total mass of , cofactor / coenzyme , very small compared to total mass of protein
idea that proteins are used for purposes other than enzymes ;
4 proteins are not stored in the body but vitamins andminerals are ;
5 some enzymes don’t need cofactors ;
52
The cells of living organisms require glucose.
State and explain two ways in which the glucose molecule is well suited to its function in
living organisms.
soluble so can be (easily) , transported / carried (around organism) ;
small (molecule) so can , be transported / diffuse , across (cell) membranes ;
easily / quickly , respired / oxidised / broken down , to , release energy / produce ATP ;
molecules can , join / AW , to produce , (named) disaccharides / (named) polysaccharides ;
53
The cytoskeleton in cells consists of microtubules and microfilaments. Describe the roles of the cytoskeleton.
1 (whole) cell, support / stability / scaffolding /
maintain shape ;
2 movement of, cilia / flagella / undulipodia OR use
of cilia / flagellum / undulipodium to move cell ;
3 changing shape of cell / cytokinesis / pseudopodia / phagocytosis / endocytosis / exocytosis /
muscle contraction ; 4 (named) organelles, moved / held in place ;
5 movement of, chromosomes / chromatids / (m)RNA ;
54
(i) Outline how the vesicles are moved from one organelle to another.
cytoskeleton / microtubule / microfilament ; provide, pathways / tracks, (for movement) ;
(vesicle) moves along, microfilaments / microtubule ; microtubules, extended / broken down
uses, ATP / (metabolic) energy ; AVP ;
55
Cells in the pancreas secrete proteins such as the enzymes pancreatic amylase and protease. Describe how these extracellular enzymes are secreted from the cells.
exocytosis ;
vesicle fuses / merges ;
(with), cell surface / plasma, membrane ;
discharging / releasing, enzyme / contents (to exterior) ;
56
Describe ways in which the physical properties of water allow organisms to survive over a range of temperatures.
V1 high latent heat of vaporisation / large amount of energy required to change from liquid to gas / AW ;
V1 ACCEPT ‘large amount of heat needed...”
V2 evaporation is (efficient) cooling mechanism / AW ; V3 example of cooling in living organism ;
V2 ACCEPT ‘evaporation removes heat from body’
H1 high specific heat capacity / large amount of energy needed to, raise / change, temperature ;
H1 ACCEPT ‘water / it, is thermally stable’
H1 ACCEPT ‘water is slow to change temperature’
H2 (thermally) stable environment for, aquatic /
named aquatic, organisms ;
H2 ‘thermally’ can be inferred from previous statement
H3 (aquatic) organisms use less energy on temperature control ;
H4 (internal) temperature of organisms changes only slowly ; H5 (biological) reactions / enzymes / metabolism, function(s)
H5 IGNORE ‘organisms function correctly’
F1 ice, is less dense than water / floats ;
F2 (surface of) ice provides habitat for, organisms / named
F1 ACCEPT ‘maximum density is at 4°C’ F2 e.g. ‘polar bears on ice’
correctly ;
organism ;
3
All marks are stand alone
V1 ACCEPT ‘high latent heat of evaporation’
V3 e.g. sweating, panting, transpiration (as cooling)
‘high latent heat of evaporat
57
Three properties of water that contribute to this stability are as follows:
• the density of water decreases as the temperature falls below 4°C so ice floats on the top of the pond
• it acts as a solvent for ions such as nitrates (NO –) 3
• a large quantity of energy is required to raise the temperature of water by 1 °C.
Explain how these three properties help organisms survive in the pond.
(ice less dense because) molecules spread out ;
S1 S2 S3
organisms do not freeze ;
animals / organisms, can still, swim / move ; allows, currents / nutrients, to circulate ;
S1 DO NOT ACCEPT die (because ‘survival’ stated in stem)
P5 P6
ions / named ion, polar / charged ;
ions /named ion, attracted to / bind to / interact with, water;
S4 S5
(named) organisms / plants / animals,
uptake / AW, minerals / named mineral / nutrients ;
S4 ACCEPT obtain / enters / goes in / gets
ice floats
molecules form, crystal structure / lattice / AW ;
ice forms insulating layer / clearly described ;
P3 e.g. acts as a barrier to the cold
water (below ice), does not freeze / still liquid /
remains water / kept at higher temperature ;
solubility
correct use of named, mineral / nutrient, in organism ;
58
State two properties of collagen that make it suitable for this purpose.
(high tensile) strength / strong ; does not stretch / is not elastic ; insoluble ;
flexible ;
59
Membranes contain a variety of proteins. Some of these proteins are combined with carbohydrates to form glycoproteins.
Describe the functions of glycoproteins in the cell surface membrane.
(acting as) antigens ;
2 identification / recognition, (of cells) as, self /
cell signalling / described ;
receptor binding site /horone
(chemical) signal / (medicinal / named) drugs ;
attach to water molecules (to stabilise
membrane / cell) ;
4 max for description
v6 cell adhesion / to hold cells together (in a
tissue) ;
ef. to receptor / binding site / trigger, on
transport proteins / AW
60
Amylase is an enzyme that hydrolyses amylose to maltose. Maltose, like glucose, is a reducing sugar.
A student investigated the action of amylase on amylose. She mixed amylase with amylose and placed the mixture in a water bath.
Describe how she could measure the change in concentration of maltose (reducing sugar) as the reaction proceeds.
take samples at a range of times / AW ;
```
same volumes (of solutions) added / removed (each time) ;
heat with, Benedict’s (solution) / CuSO4 and NaOH ;
```
(use of ) excess Benedict’s ;
changes to, green / yellow / orange / brown / (brick) red ;
remove precipitate / obtain filtrate ;
colorimeter ;
calibrate / zero, using, a blank / water / (unreacted) Benedict’s
use (red / orange) filter ;
reading of, transmission / absorbance
mass of precipitate ;
more transmission / less absorbance, of filtrate,
greater mass ppt, = more maltose present ; ora
using, standard / known, concentrations (of maltose) ; (obtain) calibration curve ;
plot, transmission / absorbance / mass of ppt, against
12 CREDIT ‘serial dilutions’
15
(reducing sugar) concentration ; use graph to read off concentration of maltose / AW ;
61
(ii) Suggest how chloride ions have this effect on the rate of reaction.
acts as a) cofactor ;
(Cl-) binds to, enzyme / amylase / amylose / substrate ;
enzyme substrate complex / ESC, forms more, easily / quickly ;
62
State where in a pancreatic cell insulin molecules are synthesised.
ribosome / rough endoplasmic reticulum / RER ;
63
Outline the events that occur after the synthesis of an insulin molecule until it is ready to
be secreted from the pancreatic cell
transported to Golgi ;
modified / processed , in Golgi ;
packaged into / stored in , (Golgi) vesicle(s) ; vesicles transported towards ,
secretion 2 DO NOT CREDIT if ref. to carbohydrate
5
AVP
64
Explain why glycogen makes a good storage molecule.
insoluble ;
2 does not , change / affect , water potential / Ψ , of cell ;
can be , broken down / hydrolysed / built up , quickly / easily ;
lots of branches for enzymes to attach ;
5 compact ;
6 (therefore) high energy content for mass / energy dense
65
smooth muscle - what does it do in the airways
constrict the airway / AW
66
Suggest one detail that would be made visible if the micrograph were taken using:
(i) a scanning electron microscope
(ii) a transmission electron microscope.
(i) a scanning electron microscope -3D shape can be seen / greater depth of field ;
(ii) a transmission electron microscope.-can see, surface features / detail ;
67
Neutrophils are phagocytic blood cells that can engulf and digest foreign cells found in the blood.
Describe how the ultrastructure of a neutrophil is specialised to enable it to perform this function.
many) lysosomes / vesicles containing enzymes ;
2 (many) microfilaments / microtubules OR
ref to, extensive / well developed, cytoskeleton ;
3 (many) ribosomes / (a lot of) rough endoplasmic
4 (many) mitochondria ;
5 (lots of) Golgi ;
6 (many) receptor (sites) on, cell surface / plasma , membrane ;
68
Proteins are produced by the structure labelled F. Some of these proteins may be extracellular
proteins that are released from the cell.
Outline the sequence of events following the production of extracellular proteins that leads to their release from the cell
proteins moved to Golgi (apparatus / body) ; processed / modified / AW ;
correct answer = two marks
3.75 / 3.8 ;;
(even if later rounded to 4)
Max 1 if response is 4 with no working
if answer incorrect ALLOW one mark for correct working
candidate shows correct calculation but wrong answer
into vesicles ;
(vesicle) moved to, plasma / cell surface, membrane ; (vesicles) fuse with membrane ;
exocytosis ;
69
State three reasons why mitosis is important to organisms.
growth (of tissue / organism) ;
replace (cells) / repair (tissues) ;
asexual reproduction/cloning / producing genetically identical
cells ;
maintain chromosome number in all cells ;
70
Suggest two advantages, other than an increased probability of survival, of using umbilical cord blood stem cells instead of bone marrow stem cells in transplant procedures.
greater availability of cord cells / more likely to find donors;
easier to harvest / no pain for donor ;
cells at earlier stage of development ;
can be stored for future, use/repair / gene therapy, of donor ;
slightly mismatched cord cells work (almost) as well as marrow cells ;
71
The bronchus wall also contains smooth muscle fibres. State the function of the smooth muscle fibres.
to constrict the bronchus / AW ;
72
Type of DNA in eukaryotic
s chromosomes / chromatin OR
| (genetic material) associated with, proteins / histones ;
73
Average diameter of eukaryotic
(diameter of cell) 20 – 40 um ;
74
Ribosome diameter in prokaryotic
(ribosomes) 18nm ;
75
Cell wall in pork
cell wall (present) ;
76
(i) Suggest one difference between lipids from animals and those from plants.
saturated ;
| (fatty acids have) no / fewer, double bonds ; solid at room temperature ;
77
Which bonds break in increase in temp
HYDROGEN BONDS
78
State two examples of active transport in cells.
For each example, you should name the substance that is transported and the cell
involved.
sodium/potassium ion(s) - cell neutron - (direction) K+ in Na+out
sodium/potassium ion(s)
named cell
Ion pump to drive cotransport
```
potassium ion(s)
guard cell (to open stomata)
in
```
calcium ions
presynaptic knob
out
79
(ii) Explain why the wall of the left ventricle is thicker than the wall of the left atrium.
```
1 (more muscle to create) more force ;
2 (needs to create) higher pressure ;
3 push blood against greater , resistance / friction ;
4 (leftventricle)pumpsbloodfurther/
pumps blood to all parts of body /
supplies systemic circulation ;
```
80
The secretion of digestive juices into the mammalian gut is controlled by the endocrine and nervous systems.
Explain some changes and what causes them
(parasymapwrhtic )
a) Sight/smell/taste of food
Parasympathetic nerve stimulates salivary gland
Saliva
Contact of food with stomach
b) Gastrin
Gastric juice
Contact of food with duodenum lining
Cholecystokinin secreted
c) Pancreatic juice/bile
Contact of food with duodenum lining
d) Secretin
Alkaline fluid from pancreas
81
Where is most of water obtained in digestive system
large intestine
82
Give four structural features of part A which suit it for its function.(villi)
shape increases surface area/large surface area; microvilli increase surface area;
many capillaries to absorb into blood/good blood supply; lacteals to absorb into lymph;
surface epithelium only one cell thick;
83
name enzymes secreted by villi ( from crypt (of Lieberkühn);
| )
peptidase/exopeptidase/endopeptidase/carboxypeptidase/aminopeptidase/ to digest polypeptides to amino acids/
maltase to digest maltose to glucose/
lactase to digest lactose to glucose and galactose/
sucrase to digest sucrose to glucose and fructose/ lipase to digest fats to fatty acids and glycerol;;;;
84
Is maltose reducing or non reducing
Reducing
85
where are Oxyntic and peptic cells present
stomach
86
Ducts from the pancreas and liver enter into here
duodenum
87
(c) What type of epithelium lines the oesophagus ? Explain why.
stratified squamous epithelium;
thick and keratinised/contains keratin;
to withstand friction/abrasion of passing food;
88
What does secretin do
increases volume of pancreatic juice secreted;
increases concentration hydrogen carbonate ions;
increases amylase secretion (but effect masked by large volume increase);
89
enzyme trypsin works best at what pH
trypsin works best in alkaline/high pH;
90
(ii) State two functions of hydrogen carbonate ions in the duodenum.
Any two of: provides alkaline pH for duodenal enzymes/neutralises stomach acid/ saponification/alkaline hydolysis of fats;;
91
(e) Suggest two main sources of error in the above experiment.
some heat from flame is lost and doesn’t heat the water;
| food may not be completely burnt/different water contents in food to begin with;
92
Small squirts of this are allowed through the pyloric sphincter into the duodenum where they cause the release of the hormones .................................. and ................................... .
s ecretin; pancreozymin;
93
What do bile salts do to fats
emulsify
94
What activates trypsinogen
enterokinase
95
In the ileum glucose is absorbed into the blood. and carried to the liver in the ................................. vein.
hepatic portal vein
96
(ii) What is absorbed into the lymphatic system?
(ii) fat/fatty acids and glycerol;
97
(c) What is meant by the term ‘assimilation’?
the utilisation by the body of the absorbed foods; as respiratory substrate/for ATP production;
or for protein/enzyme/hormone synthesis;
98
State one location where each of the following substances are released:
1. salivary glands/pancreas; 2. liver/gall bladder;
| 3. salivary glands/stomach/small intestine/large intestine/colon; 4. stomach;
99
Explain what is meant by the term organic molecule using an example from Table 2.1.
idea of a molecule containing mainly carbon and a number of other elements
sucrose / protein / amino acids, used as illustration
100
How would you measure the effect of surface area to volume on diffusion?
Rate of diffusion in agar blocks
Substances diffuse down concentration gradients
- It is possible to notice that some processes occur faster than others, but to quantify this they have to be timed.
- For example, agar can mixed with a pH indicator and an alkali
- After solidifying , the agar can be cut into pirces
- When these pices are dropped into 2.0 moldm-3 hydrochloric acid the pH changes and the indicator gradually changes colour as the acid diffuses inwards.
- Using this method we can tell how ling it takes for the aci to diffuse to the centre of an agar block
- Now imagine that these agar blocks are cells
- As cells increase in size, the relaitonshop between surface area and volume changes.
- By making blocks of different dizes it is possible to investigate the effect of surface area-to-volume (SA:V) RATE on diffusion.
101
What do bile salts do
Bile salts emulsify lipids-can provide a larger surface area for lipase to work on - will increase reaction
