Exam Ques Flashcards
Failure of structure X to develop properly in the cells of a plant root could be catastrophic to a plant.
Suggest an explanation as to why [4]
=function of root hair is to increase surface area;
-for absorption of water (by osmosis);
-for absorption of mineral ions
-Less root hairs would reduce absorption;
-Water is essential for photosynthesis
-(Reduced absorption) could lead to mineral deficiencies, causing stunted growth
Suggest how the number and distribution of rod cells and cone cells across the retina of
a nocturnal mammal would differ from a human retina.
more rods present and no / fewer cones present ;
rods at the fovea
Overfishing is one reason why populations of fish decline.
Explain the risks to a species if its population size decreases.[3]
reduction in genetic variation;
increase in the frequency of recessive alleles ;
risk of extinction ;
idea of unable to find mates;
Describe and explain how fish stocks can be managed sustainably and how overfishing can
be prevented through conservation [6]
Education/awareness is one way, making people aware of legal quotas, restricted catch weight, and existing laws that make it illegal.
Population of fish should be monitored.
Reduced demand to eat from unsustainable fish stocks, protected areas, closed-fishing seasons and captive breeding and release can also be used.
names of two enzymes that are needed to break down starch into glucose in
humans.
amylase ;
maltase
mineral ion that is used to make amino acids
nitrate
The oxygen debt needs to be removed after exercise.
State how the breathing and circulatory systems act to remove the oxygen debt.
continuation of deeper breathing / faster breathing / AW ;
continuation of fast heart rate / AW ;
idea of delivering oxygen for the breakdown of lactic acid / delivering lactic
acid to the liver to be broken down ;
Describe the stages in the reproduction of a flowering plant, from self‑pollination to
fertilisation [5]
📌 self-pollination occurs in the same plant or on the same flower
📌pollen grain is transferred from anther of one flower to the stigma of the same flower or a different flower on the same plant
📌pollen grain grows into pollen tube
📌pollen nucleus fuses with the ovule nucleus
📌zygote is formed
📌pollen releases enzymes
[-pollen nucleus travels down the pollen tube
-pollen nucleus moves through the style]
Outline the advantages and disadvantages of self‑pollination compared with
cross‑pollination. [4]
-more (chance of successful) pollination / fertilisation ;
-less pollen wasted ;
-less, variation / (genetic) diversity ;
-limited ability to, adapt to (named) change in environment ;
- more chance of, genetic / inherited, disease ;
fill in word
- increasing the carbon dioxide concentration caused more starch to be
produced in the leaves. This shows that, at a normal carbon dioxide concentration, carbon dioxide is a LIMITING FACTOR for photosynthesis.
During photosynthesis, SIX molecules of carbon dioxide are required to make one molecule of glucose.
The greater quantity of starch stored in the leaves grown in a high carbon dioxide concentration means, when needed, more sucrose can be produced for transport in the phloem, so the leaves act as a SOURCE.
The greater number of chloroplasts per cell in the leaves grown in the higher carbon dioxide concentration means that more energy can be absorbed from LIGHT and transferred to CHEMICAL energy.
The transpiration rate is lower when the carbon dioxide concentration is higher. This means reduced loss of WATER VAPOUR from the leaves.
Magnesium ion concentration is lower in these leaves because they have used the magnesium ions to make CHLOROPHYLL.
Explain how the structure of a capillary is related to its function [3]
any 3 of:
allows delivery of named useful substances (to tissues) / removal of named
waste ;
thin (capillary) wall / wall is one cell thick ;
small lumen / AW ;
short diffusion distance / close contact ;
slows down blood flow (to maximise time for diffusion) ;
gaps between (capillary) cells ;
Explain the effect of exercise on the rate and depth of breathing shown [4]
- increases rate and depth of breathing due to oxygen ebing required for aerobic respiration
-exercise uses muscle which need more energy
-increased carbon dioxide concentration in the blood lowers the pH,
-which is detected by the brain
-adrenaline release during exercise increases breathing rate
When the temperature moves away from the set point, the mechanism of ______________________ returns the
temperature to the set point.
negative feedback
Describe how humans maintain a constant body temperature when the external temperature decreases. [6]
detects (sensory to brain, along motor)
hairs
fatty tissue
vaso
any 6 of:
thermoreceptor detects stimulus / decrease (in temperature) ;
hairs stand up ;
(hairs) trap layer of air as insulation ;
fatty tissue acts as insulation ;
shivering to keep warm ;
vasoconstriction ;
(vasoconstriction) decreases blood flow to the surface ;
[- impulse sent along sensory neurone to, hypothalamus (in brain) ;
- impulses from the brain, travel along motor neurone ;]
effect of glucagon on the body
(stimulates) the breakdown of glycogen (to glucose) ;
increases (blood) glucose (concentration) ;
