Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Science B1 Topic 2
GCSE edexcel core science biology: responses to a changing environment
| Question | Answer |
|---|---|
| What is homeostasis? | The maintenance of a stable internal environment |
| What is osmoregulation? | The control of water in the body |
| What are the issues if the body has too much water? | It causes swellings and high blood pressure |
| What are the homeostatic mechanisms used when there is too much water in the body? | * Kidneys produce more urine * Urine is more dilute * Glands produce more sweat |
| What are the issues if the body doesn't have enough water? | Chemical reactions can't take place |
| What are the homeostatic mechanisms used when there is too little water in the body? | * Kidneys produce less urine * Urine is stronger (less dilute) * Brain responds by making you feel thirsty |
| What is blood glucose regulation? | Homeostatic mechanism which controls the glucose concentration in blood |
| What is thermoregulation? | Control of the body temperature (which has to be kept at 37 degrees Celsius) |
| What is the hypothalamus? | It's the part of the brain that monitors body temperature |
| What homeostatic mechanisms are used when the body is too hot? | Hypothalamus causes: * vasodilation (widens blood vessels near skin surface) * Sweat gland releases sweat * erector muscle relaxes so hairs lie flat |
| What homeostatic mechanisms are used when the body is too cold? | Hypothalamus makes: * erector muscle in dermis contract so hairs stand up and trap air as insulation * sweat glands don't produce sweat * muscles shiver which releases heat * blood flow is reduced to skin surface by vasoconstriction (narrow blood vess |
| What is negative feedback? | A control mechanism that reacts to a change in condition by trying to bring the condition back to normal level (e.g. body gets hot, then tries to cool it down to bring the temperature back to normal) |
| What is the dermis? | the layer of skin where the blood vessels and nerve endings are found |
| What do oils from the sebaceous glands do? | They keep the skin in good condition (and are found at the base of hairs) |
| What is the CNS made up of? | The spinal chord and the brain |
| What are nerves? | Nerves are bundles of neurone cells |
| What is a stimulus? | A change in environmental factors |
| Which cells detect stimuli and what do they do? | Receptor cells detect stimuli and create impulses which travel along nerves to the brain |
| What is the process of impulses travelling along nerves called? | Neurotransmission |
| What are impulses? | Electrical signals |
| What does the axon do? | It carries the impulse away from the cell body |
| What does the dendron do? | It carries the impulse to the cell body |
| What are sensory neurones? | Neurones that receive impulses from receptor cells and send them to the CNS |
| What is a sensory neurone made up of? | Dendrites at the end of the dendron, the dendron, the cell body, the axon, the myelin sheath and the dendrites at the end of the axon |
| What are motor neurones? | Neurones that take impulses from the CNS to the effectors e.g.muscles and glands |
| What is a motor neurone made up of? | Cell body, dendrites on the cell body, axon, dendrites at the end of the axon, myelin sheath |
| What are relay neurones? | Relay neurones are short neurones that make up the brain and are found in the spinal chord where they link motor and sensory neurones |
| What is a relay neurone made up of? | Cell body with dendrites on to receive the impulses and longer dendrites to pass the impulses on to other neurones |
| What is the role of the myelin sheath? | It is a fatty insulating layer around the axon which: - insulates the neurone from surrounding tissue - makes the impulse travel faster |
| What is a synapse? | A synapse is a gap between two neurones where they connect |
| How do impulses travel across synapses? | By chemical substances called neurotransmitters- these are released from axon endings and carry the impulse across the synapse to the next neurone |
| What is the issue with synapses? | They slow the impulse down |
| Why are synapses useful overall? | Although they slow the impulse down, they make sure that the impulses only travel in one direction (which is very important) |
| What are reflex actions? | Automatic, fast responses that are used in situations to protect the body |
| What are reflex paths? | They are the neurone pathway that reflex responses follow- the impulse goes straight from the sensory neurone to the motor neurone, bypassing the relay neurones and parts of the brain involved in conscious thought |
| What are some examples of reflex actions? | Moving hand off something hot, pupils get smaller in bright light, blinking when something comes towards your face. |
| What are hormones and how are they produced/transported? | Chemicals whose presence causes certain parts of the body to respond in a certain way- they are produced and released by the endocrine glands, and travel in the blood to the target organ |
| What is adrenaline (and what is it produced by, target organ, effect)? | Adrenaline is a hormone that is produced by adrenal glands and causes the heart to beat faster |
| What is anti-diuretic(and what is it produced by, target organ, effect)? | Anti-diuretic is a hormone that is produced by pituitary gland and causes the kidneys to produce more concentrated urine |
| What happens to the blood glucose levels when you exercise- and what happens as a result of this? | The blood glucose levels decrease, so the pancreas secretes glucagon, which is a hormone that causes the liver to break down glucogen into glucose- making the blood glucose levels normal again |
| What happens to the blood glucose levels when you eat- and what happens as a result of this? | The blood glucose levels increase- so the pancreas secretes insulin, a hormone that causes the liver to turn glucose into glycogen (a glucose storage), which makes the blood glucose levels normal again. |
| What is diabetes? | A disease that means blood glucose levels can't be controlled well |
| What happens if someone has very low blood glucose concentration? | It can cause unconsciousness |
| What happens if someone has very high blood glucose concentration? | It can cause damage to organs (such as the eyes) and can cause tiredness- kidneys as a result put more glucose in the urine |
| What is type 1 diabetes? | When the pancreas doesn't produce any/enough insulin |
| How can type 1 diabetes be controlled? | Insulin is injected into the subcutaneous fat layer, a person should do plenty of exercise, and they should eat a balanced diet with a controlled amount of carbohydrate |
| What impacts the amount of insulin required on certain days for a person with type 1 diabetes? | Physical activity and less sugary diet = less insulin. Less physical activity and more sugary foods = more insulin |
| Why is exercise good for controlling diabetes? | Glucose is used up in respiration by cells |
| What is type 2 diabetes? | When the cells in the body do not respond to insulin- they become 'resistant' to it |
| What sort of issues can lead to a person having type 2 diabetes? | High fat diets, lack of exercise, obesity, getting older |
| How can type 2 diabetes be controlled? | Changing a person's diet to eat less sugary/fatty food and doing more exercise |
| What is BMI? | Body mass index- it is a calculation that gives an estimate of how healthy a person is for their height |
| What is the formula for working out BMI? | weight in kg/ (height in m) squared kg/m^2 |
| At what BMI is one classified as obese? | 30 and over |
| What can a high BMI (obesity) cause? | It can cause health diseases such as type 2 diabetes |
| What is a tropism? | A response to a stimulus by growing towards or away from it |
| What is a positive/ a negative tropism? | A tropism towards/ away from a stimulus |
| What is a stimulus? | A change in environmental factors |
| What controls plant sensitivity? | Hormones (plant growth substances) because plants don't have a central nervous system |
| What are auxins/ what do they cause (in shoot tips)? | Auxins are plant hormones that cause positive phototropism- they are found in plant shoot tips and cause shoots to grow towards the light so that they get enough light for photosynthesis |
| How do auxins cause plant shoots to grow towards the light? | They move onto the shaded side of the plant and cause cell elongation on that side. This makes the plant bend towards the light |
| What do auxins do in root tips? | They are pulled down to the bottom side of the root tip, and inhibit cell elongation. This causes positive gravitotropism/geotropism, as it causes the plant to grow towards to direction of gravity |
| Why do auxins cause this in plant roots? | It anchors the plant in the ground and allows the roots to reach moisture and nutrients underground |
| What are giberellins and what do they cause? | They are plant hormones that cause germination of seeds (as they turn starch into glucose for growth) and they stimulate flower and fruit production |
| What are the 4 uses of plant hormones? | 1)selective weedkiller 2)rooting powder 3)seedless fruit 4)fruit ripening |
| How can plant hormones be used for selective weedkillers? | Artificial auxins are sprayed over crops. Most weeds are broad-leaved, so these auxins cause them to grow out of control and die. However, a farmer's crop stays unaffected, as most cereal crops have narrow leaves |
| How can plant hormones be used for rooting powder? | Cuttings (parts of plants) are dipped in rooting powder, which contains synthetic auxins. The growth hormones in the powder make the roots develop quickly, so alrge numbers of the same plant can be grown quickly |
| How can plant hormones be used for producing seedless fruit? | Flowers are sprayed with plant hormones that cause the fruit to develop but not their seeds. Most naturally seedless grapes are small, so giberellins are sprayer over them to increase their size. |
| How can plant hormones be used for fruit ripening? | *fruit can be picked when unripe, so it is firmer and less damaged, and is sprayed to ripen and grow larger * sprayed on fruit trees to speed up ripening so all fruit is picked in one go *fruit is picked unripe to arrive on shops shelves "just ripened" |
Created by:
11043
Popular Biology sets