Bio paper 1 Exam Questions Wrong Answers Flashcards
Explain the advantages of red blood cells passing through a capillary one at a time? (3marks)
- B1 - cell structure
More oxygen is released to tissues/ more oxygen taken up from lungs.
Shorter distance (for exchange)
What domain are fungi classified in?
eukaryota
what are 5 types of evidence used to classify living things?
- 3 marks
- DNA analysis
- studies of internal/ cell structure with electron microscopes
- chemical analysis
- comparison of biochemical processes
- studies of evolutionary relationships
give one way the nucleus of the sperm is different to the nucleus of the body cells?
has half the number of chromosomes
suggest why antibiotics that disrupt the bacterial cell membrane often cause more side effects in humans compared with antibiotics that disrupt bacterial cell walls
- 1 mark
human cells have no cell wall
some people think that governments should pay drug manufacturers to develop new antibiotics.
suggest why
- 3 marks
- antibiotics are being developed at a slower rate than the emergence of new resistant strains
- resistant strains means we cannot treat (common) infections
- reduce (future) cost of antibiotic resistance infections
what is the function of WBCs? 1 mark
fight/ingest/kill bacteria/viruses/ microobes
why is it important for the nerve cell to detect stimuli?
- 3 marks
- to react/ respond to the surroundings
- avoid dangers/ protect the body
- to coordinate behaviour/ process information
what controls the rate of chemical reacrions
explain the significance of the nucleus in determining the characteristics of the offspring?
contains chromosomes/ genes/ DNA (1)
which contribute half the genes to the offspring (1)
describe how nitrate ions are used in a plant to help the plant grow?
- 3 marks
nitrate ions are used with glucose (1)
to form amino acids (1)
which are used to synthesise proteins needed for growth (1)
A plant cell is put into water and swells up, explain why.
- 3 marks
water enters the cell (1)
by osmosis/diffusion (1) through a partially permeable membrane (1)
the genetic material is arranged differently in cells of bacteria compared with animal and plant cells, describe 2 differences.
- only one chromosomes
- circular
- may have plasmids
- not in a nucleus
why is it necessary to absorb some food molecules by active transport?
- 1 mark
against a concentration gradient
suggest why epithelial cells have many mitochondria?
active transport requires energy from from respiration
explain how releasing sterile mosquitos reduces the spread of malaria?
- 2 marks
reduces breeding/ prodction in mosquitos (1) so fewer mosquitos bite people/ fewer mosquitos pass on pathogen/protist (1)
what is the function of haemoglobin/ red pigment?
- 2 marks
carries oxygen (1) from lungs to tissues (1)
explain one way sieve tubes cells are specialised for their function?
- 2 marks
have pored in the end walls (1) so dissolved sugars can move from cell to cell (1)
or
they have no nucleus/ few sub-cellular structures (1) to maximise space for movement of dissolved sugars
describe why it is important for dissolved sugars to be moved both upwards and downwards in a plant.
- 3 marks
sugars are made in leaves by photosysnthesis (1)
all cells/ tissues need sugar for respiration (1)
sugars are transported ti meristems for growth/ cell division/ mitosis
or
sugars are transported for storage as starch/ fat/ oil (1)
explain how cell enlargement is part of the growth process for a baby? (3)
- cells have to get bigger
2.cells have to mature to divide - cells which are bigger take up more space
why is cell specialisation important for the development and growth of a baby?
- babies need difference cells that have different functions
- specialised cells undergo mitosis to grow further cells
give one feature of the cell wall that allows the cell to become turgid?
cell is strong/ elastic
explain why single- celled organisms like algae do not need complex structures for gas exchange? (3 marks)
cell has larger SA: Vol ratio (1 mark)
short diffusion distance (1 mark)
diffusion via cell membrane is sufficient or flow of water maintains concentration gradient ( 1 mark)
explain why translocation is important in plants?
(2 marks)
sugars are made in leaves (1 mark)
so they need to be moved to other parts of the plant for respiration/ growth (1 mark)
explain why active transport is important in root hair cells?
( 2 marks)
for movement of minerals / ions ( 1 mark)
against their concentration gradient (1 mark)
what is the function of mitochondria? (2 marks)
To transfer energy for use (1) by aerobic respiration (1)
give 3 features of the plant and how it helps the plant to absorb mineral ions from the soil.
- thousands of root hairs —> large SA
- many mitochondria –> aeorbic respiration gives/ releases energy
- many of the cells in the root store starch –> starch is an energy source/ store (for active transport)
decribe 4 difference between bacteria cell and plant cell? (7)
- bacteria cell does not have mitochondria
- bacteria cell is smaller than plant cell
- bacteria cell does not have chloroplasts
- bacteria cells may have plasmids
- cell wall within bacteria cell is not made of cellulose
- bacteria cell does not have a large/ permanent vacuole
- bacteria cell has smaller ribosomes
explain how vaccinating chickens reduces the number of cases of salmonella food poisoning?
few bacteria/ pathogens in chicken/food (1) so fewer bacteria ingested by humans (1) /so fewer toxins produced
why is the number of cases of salmonella food poisoning higher in summer than in winter?
(1 mark)
warmer weather so bacteria reproduces faster
give 2 uses of energy transfered in eukaryotes? (3)
- synthesis of new molecules
- for active transport
- to keep warm (mammals/ birds)
compare the processes of anaerobic respiration in muscle and plant cells (4)
- both occur without oxygen
- both releases ( a small amount of energy)
- muscle cells produces lactic acid but plant cells produce ehanol
- muscle cell do not produce CO2 but plant cells do
what is an enzyme? ( 2 marks)
a catalust that speed up a reaction (1 mark) it is a protein/ specific/ has an active site (1)
explain how the villi are adapted for efficient absorption of sugar molecules?
- have micro villi – to increase SA
- one cell thick/ thin —> short pathway
- good blood supply –> maintain a diffusion gradient / transport food molecules away/ to the body
- cells have mitochondria –> where respiration takes place / where energy is transferred/ as active transport requires energy/ energy is needed to absorb sugar/ food
Advantages (4) and disadvantages (5) of theraputic cloning in medical treatments
Advantages:
1. may be used to cure/treat diseases
- produce replacement cells/ tissues
2. cells/ tissues of any type could be produced
3. cells produced could be used for research
4. could reduce waiting time for organ transplants
Disadvantages:
1. potential life is killed/ destroyed
2. shortage of donors/ eggs
3.egg donation/ collection has risks
4. do not yet know the risks/ side effects of the procedure on patients
5. may transfer viral infection
B2 heart
explain why beta blockers can cause some people to get out of breath when they excercise?
effect of exercise
• during exercise body needs to transfer (more) energy
• energy transferred during respiration
• rate of respiration increases during exercise
• (so) more oxygen is needed
effect of beta blockers
• beta blockers reduce (the increase in) heart rate (during exercise)
• beta blockers reduce stroke volume (or described)
• beta blockers reduce cardiac output
• (so) heart cannot supply oxygen fast enough / in sufficient quantity to muscle cells
effect on breathing rate
• breathing rate increases to increase rate / amount of oxygen absorbed
• breathing rate increases to increase rate / amount of carbon dioxide removed from body
• (but) increased breathing rate cannot fully compensate for changes in heart function
give 2 factors that effect the concentration of cholesterol in the blood?
- diet
- genes
why is the heart described as an organ?
it is made up of different tissues ( that perform specific functions)
explain the effects on a person if the valve (on the figure) developed a leak?
some blood would flow back into the left ventricle
allow not all the blood would leave the left ventricle
1
(so) less oxygenated blood would be pumped to the body
ignore references to glucose
1
cells require oxygen for respiration
or
less aerobic respiration
allow more anaerobic respiration
1
(so) person would become out of breath
(so) lactic acid will build up
or
(so) less energy transferred
or
(so) person would be tired
allow the idea of lacking energy
explain why heart attack survivors get out of breath easily?
heart (muscle) cannot contract / pump as effectively / powerfully
allow heart (muscle) is not as strong
1
(so) less blood pumped out of heart or to body (on each beat / contraction)
ignore reference to rate of blood flow
1
(so) less oxygen (reaches cells / body) for (aerobic) respiration
allow (so) more anaerobic respiration
1
(so) breathing rate increases to supply more oxygen
or
(so) breathing rate increases to repay oxygen debt
allow (so) breathing rate increases to break down lactic acid
how do arteries supplying the leg muscles alter the rate of blood flow through them during excercise?
arteries dilate / widen
explain how an increase in heart rate helped the student during excercise?
- muscles using more energy/ more energy released
- muslces respire faster
- supply more oxygen
- remove CO2
remove lactic acid - remove heat to cool
give 2 changes in the body that help to increase the amount of oxygen delivered to the working muscles during excercise?
- increasing breathing rate
- increased depth of breathing
- dillation of arteries
- blood diverted from elsewhere
give one way the arteries is different from the vein
pulmonary artery has less oxygen
what type of tissue is the wall of the heart made of?
muscle/ muscular
B3 role of immune system
explain how the MRSA bacterium has developed resistance to antibiotics? (2 marks)
mutation (1)
no longer recognised by anitbiotics (1)
what do antitoxins do?
destroy pathogens/ neutralise toxins
name 3 chemical substances transported by the plasma
- carbon dioxide
- water
- amino acids
- antibodies
- antitoxins
- cholesterol
- enzymes
- fatty acids
- glucose
- glycerol
- hormones
- ions
- proteins
- urea
- vitamins
explain why vaccination against the measles virus will not protect the child against the rubella virus? (1 mark)
antibodies are specific
After being injested, the microbes are digested in the cells. Briefly explain what happens to the proteins that the microbes contain?
they are broken down by enzymes into amino acids
name 2 types of microbes which cause disease in humans?
bacteria and pathogens
explain why (BCG) vaccine is not effective as a cure for people who already have (tuberculosis)?
(2 marks)
adds more bacteria (1)
does not affect TB bacteria (1)
antibodies have specific shapes which attach to the antigen
suggest the possible cause of the reaction when a person who is already immune is tested ( as shown in diagram A).
(2 marks)
antibodies in blood/ skin/ body (1)
react with injected antigens or bacteria (1)
suggest why a second dose / booster vaccine is necessary?
so more antibodies are made
B2 Transpiration
give 3 environmental conditions that would increase transpiration
- hot
- dry/ low humidity
- windy
suggest one reason for the decrease in the rate of transpiration in evening?
gets darker (1)
so stomata opens more (1)
explain why roots need to use osmosis and active transport to absorb water and ions?
solution in soil is more dilute than in root cells (1)
so water moves down its concentration gradient (1)
concentration of ions in soil is less than in root cells (1)
so energy is needed to move ions/ ions are moved against conc gradient (1)
what is meant by the transpiration steam? (5)
movement of water from roots/ hairs (1)
via xylem (1)
to the leaves (1)
water evaporates (1)
via stomata (1)
how are ions absorbed into plants?
by diffsusion/ active transport
from high –> low conc
B1 Osmosis, active transport, diffusion
Name one food molecule absorbed into epithelial cells by active transport?
Sugar/ glucose
Suggest why epithelial cells have many mitochondria?
Active transport requires energy from respiration
Does osmosis require energy?
No it is a passive process
Explain why there are more stomata on the lower surface of the leaf?
- it is cooler around lower surface
- more humid around lower surface
- so less water is evaporated
Give 2 features of the cell wall that allows it to become turgid?
- Fully permeable
- Elastic/ strong
Describe the change which will occur if a piece of peeled potato is placed in a concentrated sugar solution and explain why this change occurs. (4 marks)
Potato shrinks (1) because the concentration of sugar (1) is greater than concentration inside the cell/ vacuole (1) water is drawn out of the cell (1)
Describe how ions and sugars are obtained and transported through the plant.
examples of points made in the response Ions:
(P) taken up by diffusion or active transport
• from an area of high to low concentration (diffusion) or an area of low to high concentration (active transport)
(V) travels in the xylem
(M) to the leaves or from the roots / soil
Sugar:
(P) made during photosynthesis
(V) travels in the phloem
(M) to other parts of the plant or to storage organs or travels up and down
Name two substances that travel from the muscle cells to the blood in the capillaries. (4)
Water
CO2
Urea
lactic acid
Glucose is one substance that travels from the blood in the capillaries to the body cells. Explain how this happens.
higher concentration of glucose or more glucose in blood than cells
1
diffuses across
1
Explain one way sieve tubes are specialised for their funcion
have pores in the end walls
allow sap for dissolved sugars
1
(so) dissolved sugars / food / contents can move from cell to cell
or
no nucleus or few / no sub-cellular structures (1)
allow few / no organelles
ignore cells are empty
to maximise space for movement of dissolved sugars / food / contents (1)
allow thick / rigid cell wall (1) to withstand pressure inside cell
Describe why it is important that dissolved sugars are moved both upwards and downwards in a plant.
sugars are made in the leaves by photosynthesis
allow glucose for sugar
allow sugars are not made in the root / meristems (by photosynthesis)
1
all cells / tissues need sugar for respiration
allow every cell / tissue needs sugar for respiration
allow whole plant needs sugar as an energy source
1
(sugars) transported to meristems for growth / cell division / mitosis
or
(sugars) transported for storage as starch / fat / oil
Give 2 uses of energy transferred by respiration in eukaryotes
any two from:
• synthesis of new molecules
allow named molecule eg starch / glycogen / cellulose / lipids / fats / proteins / hormones / antibodies
• for active transport
• to keep warm (in mammals / birds)
allow description
allow to keep warm (in animals)
allow for movement (in animals)
allow for transmission of nerve impulses (in animals)
