Biology Paper 2 (Content) Flashcards
What is CNS?
- Stands for Central Nervous System
- Brain and Spinal chord
What is type 1 diabetes?
- A disorder where the pancreas fails to produce enough insulin. People with type 1 diabetes have uncontrolled high blood glucose levels
What is type 2 diabetes?
In Type 2 diabetes the body cells no longer respond to insulin produced by the pancreas. Obesity is a risk factor for Type 2 diabetes.
How is Type 1 diabetes treated?
Insulin injections
What is the treatment for Type 2 diabetes?
A carbohydrate controlled diet and an exercise routine are common treatments.
What is DNA?
DNA is a polymer made up of two strands forming a double helix.
What is a gene?
A gene is a small section of DNA on a chromosome. Each gene codes for a particular sequence of amino acids, to make a specific protein.
What are the four bases of DNA?
DNA contains four bases, A, C, G and T
What is the DNA polymer made up of?
The DNA polymer is made up of repeating nucleotide units.
What is PNS?
- Stands for Peripheral nervous system
- All of the nerves in the body
Which one is CNS and which one is PNS?
- Left = CNS
- Right = PNS
What is the pathway through the nervous system?
Stimulus → Receptor → Coordinator → Effector → Response
What is a nerve?
A bundle of neurones
What is a reflex action?
- An involuntary (or reflex) action which does not involve the conscious part of the brain as the coordinator of the reaction
- Actions are automatic and rapid
What are the three types of neurones in a reflex action
- Sensory neurone
- Motor neurone
- Relay neurone
What type of neurone is this?
Sensory Neurone
What type of neurone is this?
Relay Neurone
Motor Neurone
What is a synapse?
The junction (gap) that separates neurones
What is the cerebral cortex?
The outer layer of the brain responsible for consciousness, intelligence, memory and personality
What is the cerebellum?
Underneath the cerebral cortex in the brain and is responsible for balance, muscle coordination and movement
What is the medulla?
The medulla in the brain controls unconscious activities such as heart rate and breathing
Label the brain
A = Cerebellum
B = Medulla
C = Pituitary Gland
D = Cerebral Cortex
What is homeostasis?
- Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes
- Homeostasis maintains optimal conditions for enzyme action and all cell functions
- (Examples) In the human body: Blood glucose concentration, Body temperature and Water levels
What is the function of the cornea? (Function = what does it do?)
Transparent (clear) lens that refracts (bends) light as it enters the eye
What is the function of the iris? (Function = what does it do?)
Controls how much light enters the pupil
What is the function of the lens? (Function = what does it do?)
Transparent disc that can change shape to focus light onto the retina
What is the function of the retina? (Function = what does it do?)
Contains light receptor cells - rods (detect light intensity) and cones (detect colour)
What is the function of the optic nerve? (Function = what does it do?)
Carries sensory nerve impulses between the eye and the brain
What is the function of the pupil? (Function = what does it do?)
Hole that allows light to enter into the eye
What is the major role of the human endocrine system
Hormonal coordination and control
Describe briefly how does the Endocrine system work
The endocrine system is composed of glands which secrete chemicals
called hormones directly into the bloodstream. The blood carries the
hormone to a target organ where it produces an effect
The effects of the endocrine system are ……….. but act for longer in compared to the nervous system
1-slower
2-Longer
What is the pituitary gland?
The pituitary gland in the brain is a ‘master gland’ which secretes
several hormones into the blood in response to body conditions
Identify the following on the figure below:
1- Pituitary Gland
2- pancreas
3- ovary
4- testes.
Name the gland which monitors and controls the concentration of glucose sugar in blood.
Pancreas
What does the pancreas produce to bring down the glucose concentration in blood when it becomes too high?
Insulin
How does the Insulin bring down the blood glucose sugar concentration when it’s too high?
It causes glucose to move from the blood into the
cells
In liver and muscle cells excess glucose is converted to ……………
for storage
glycogen
Define ‘‘Type 1’’ Diabetes and how it is normally treated?
Type 1 diabetes is a disorder in which the pancreas fails to produce
sufficient insulin. It is characterised by uncontrolled high blood glucose levels and is normally treated with insulin injections.
Define ‘‘Type 2’’ Diabetes and how it is normally treated?
In Type 2 diabetes the body cells no longer respond to insulin produced by the pancreas. A carbohydrate controlled diet and an exercise regime are common treatments.
Obesity is a risk factor for which type of Diabetes?
Type 2
refer to note 1
refer to note 1
refer to note 1
Explain the effect on cells of osmotic changes in body fluids
Water leaves the body via the lungs during exhalation.
Water, ions and urea are lost from the skin in sweat.
There is no control over water, ion or urea loss by the lungs or skin.
Excess water, ions and urea are removed via the kidneys in the urine.
If body cells lose or gain too much water by osmosis they do not
function efficiently.
What does the digestion of protein from a diet result in?
Amino Acids
In the liver these amino acids are deaminated to form ammonia which is toxic. How does this toxic Ammonia get safely excreted?
Ammonia is immediately converted to urea for safe excretion.
Describe the function of kidneys in maintaining the water balance of the body.
The kidneys produce urine by filtration of the blood and selective
reabsorption of useful substances such as glucose, some ions and
water.
Explain how does the ADH hormone controls the water level in the body.
ADH is released by the pituitary gland when the blood is too concentrated and it causes more water to be reabsorbed back into the blood from the kidney tubules. This is controlled by negative feedback.
What cause secondary sex characteristics to develop and when?
1- Reproductive hormones cause secondary sexcharacteristics to develop.
2- During Puberty.
What is the name of the main female reproductive hormone? and where does it get produced?
1- Oestrogen
2- Ovaries
Define Ovulation.
Ovulation is when eggs begin to mature at puberty and one is released approximately every 28 days.
What is the name of the main male reproductive hormone and what gland is responsible for its production.
1- Testosterone
2- Testes
What is the role of the main male reproductive hormone?
It stimulates sperm production.
Several hormones are involved in the menstrual cycle of a woman. Name these hormones and explain how they are involved in this cycle.
1- Follicle stimulating hormone (FSH) causes maturation of an egg in the ovary.
2- Luteinising hormone (LH) stimulates the release of the egg.
3- Oestrogen and progesterone are involved in maintaining the uterus lining.
List Examples of hormonal methods to control fertility.
1- Oral contraceptives that contain hormones to inhibit FSH production so that no eggs mature
2- Injection, implant or skin patch of slow release progesterone to inhibit the maturation and release of eggs for a number of months or years.
3 - Surgical methods of male and female sterilisation.
List Examples of non-hormonal methods to control fertility.
1- barrier methods such as condoms and diaphragms which prevent the sperm reaching an egg.
2- intrauterine devices which prevent the implantation of an embryo or release a hormone.
3- spermicidal agents which kill or disable sperm.
4- abstaining from intercourse when an egg may be in the oviduct.
Explain how does the ‘‘In Vitro Fertilisation (IVF)’’ treatment works.
- IVF involves giving a mother FSH and LH to stimulate the maturation
of several eggs. - The eggs are collected from the mother and fertilised by sperm from the father in the laboratory.
- The fertilised eggs develop into embryos.
- At the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus (womb).
What are the disadvantages of fertility treatment?
1- it is very emotionally and physically stressful
2- the success rates are not high
3- it can lead to multiple births which are a risk to both the babies and the mother.
What is the name of the gland responsible for the production of Adrenaline and explain its role.
Adrenaline is produced by the adrenal glands in times of fear or stress. It increases the heart rate and boosts the delivery of oxygen and glucose to the brain and muscles, preparing the body for ‘flight or fight’.
What is the name of the gland responsible for the production of Thyroxine and explain its role.
Thyroxine from the thyroid gland stimulates the basal metabolic rate. It plays an important role in growth and development.
Thyroxine levels are controlled by ……………. ?
Negative Feedback.
What is the role of hormones produced by plants?
Plants produce hormones to coordinate and control growth and
responses to light (phototropism) and gravity (gravitropism or
geotropism).
What does the unequal distribution of Auxin cause ?
Unequal distributions of auxin cause unequal growth rates
in plant roots and shoots.
What are Gibberellins important for?
initiating seed germination.
What controls cell division and ripening of fruits.
Ethene.
List 3 uses of Auxin in agriculture and horticulture
1- as weed killers
2- as rooting powders
3- for promoting growth in tissue culture
List 3 uses of Gibberellins in agriculture and horticulture
1- end seed dormancy
2- promote flowering
3- increase fruit size.
