Biology (B5) Flashcards
Name the 6 glands/organs in the endocrine system
Thyroid gland, pituitary gland, pancreas, adrenal gland, testes, ovaries
State the hormone that is released from the adrenal gland and its effect on the body
Adrenaline - ‘fight or flight’ (heart rate increases, blood directed to muscles, air passages dilate)
State the hormone that is released from the thyroid gland and its effect on the body
Thyroxine - increases metabolism (chemical reactions)
State the hormones that are released from the pituitary gland and their effect on the body
FSH (egg development) & LH (ovulation)
State the hormone that is released from the testes and its effect on the body
Testosterone - puberty & sperm production (in boys)
State the hormones that are released from the ovaries and their effect on the body
Oestrogen - causes uterus lining to rebuild; Progesterone - maintains uterus lining
Which two systems help to control homeostasis?
Nervous system and endocrine system
Which disease is linked to an inability to control your blood glucose levels?
Diabetes
Define ‘homeostasis’
Regulation of internal conditions of a cell or organism to maintain optimum conditions
State three reasons for organisms requiring homeostasis
1) So cells don’t burst (too much water) 2) So enzymes work properly (temperature) 3) So chemical reactions occur (water and glucose)
State 4 things that are regulated in the body
Body temperature, blood glucose, water levels, ion levels
Which part of the body detects and controls body temperature?
Thermoregulatory centre (in the brain)
State three ways that your body increases your body temperature if you get too cold
1) Muscles contract and relax (shiver) to release thermal energy due to respiration 2) Blood vessels in skin constrict to reduce blood flow and thermal energy loss 3) Hairs on arms stand on end, trapping air beneath them
State three ways that your body decreases its temperature if you get too hot
1) Sweat glands release sweat which evaporates - transferring thermal energy to the air 2) Blood vessels in skin dilate so blood flow increases and more thermal energy lost 3) Hairs on arms lay flat
What happens to the enzymes in your body if you get (a) too hot (b) too cold?
(a) Too hot = denatured; (b) Too cold = work too slowly
Define ‘CNS’
Central Nervous System (brain and spinal cord)
Define ‘PNS’
Peripheral Nervous System (neurones)
Define ‘stimulus’
A change in the environment detected by receptors e.g. light, temperature, pressure, smell
Define ‘receptor’
Specialised cells that detect the stimulus e.g. tongue, skin, nose, eye
Define ‘effector’
Muscle/gland that responds to the motor neurone to cause a change
Define ‘sensory neurone’
Neurone carrying electrical impulse FROM receptor to CNS
Define ‘motor neurone’
Neurone carrying electrical impulse FROM the CNS to effector
Define ‘relay neurone’
Neurone carrying electrical impulse from one part of the CNS to another
Define ‘reflex response’
Rapid response which does not use conscious part before response occurs
Describe how messages are sent through the nervous system
Through neurones (electrical)
Describe how messages are sent through the endocrine system
Through blood (chemical)
Which system (nervous or endocrine) transfers messages around the body quicker?
Nervous
Which system (nervous or endocrine) does the response last for longer?
Endocrine
Which gland is called the ‘master gland’?
The pituitary gland
Define ‘synapse’
A gap or junction between two neurons
How does an impulse transfer across a synapse?
By chemical messages (Neurotransmitters)
What is the independent variable in reaction time experiments?
Attempt number
What is the dependent variable in reaction time experiments?
Reaction time (s)
Name 3 control variables in reaction time experiments
1) Same hand used 2) Same person dropping ruler 3) Hand placed in same position each time
How is the reaction time measured?
A ruler is dropped and caught and the distance on the ruler is recorded
Name one source of error in the reaction time method
Measuring the distance from a different place on the ruler each time
Give two ways to improve the accuracy of the results in reaction time experiments
1) Measure from above the thumb 2) Use a computer programme
How do we turn the distance on the ruler to a reaction time?
Use a conversion chart to turn the distance into a time
Name the equipment used in reaction time experiments
Metre rule, chair, table, partner
Describe where the hand should be placed in reaction time experiments
Place the forearm of your arm across the table with your hand overhanging the edge of the table
Describe where the ruler should start from in reaction time experiments
The bottom of the ruler at 0cm between the thumb and forefinger
Describe how the ruler should be dropped in reaction time experiments
Your partner drops the ruler without telling you
Describe how the ruler should be caught in reaction time experiments
As quickly as you can between thumb and forefinger
Name one risk in the reaction time investigation
Care should be taken to avoid injury from the falling ruler
What results should you see in reaction time experiments?
As the number of practice attempts increases, the reaction time decreases
What are possible variations on the reaction time method?
1) Effect of sugary drinks 2) Effect of caffeine 3) Effect of age
State the location & function of the cerebral cortex
Outer section - perception, memory, language
State the location & function of the cerebellum
Base of brain - balance & co-ordination of voluntary movement
State the location & function of the medulla
In brain stem - controls involuntary functions e.g. breathing
Why is it difficult to investigate brain function?
Lots of different areas work together
State three ways of investigating brain functions & regions
Brain damage patients, electrical stimulation of brain regions, MRI scanning
State two changes that can occur in the eye
Accommodation (for focussing on near/far objects), Adaptation to dim/bright light
State two things that the eye organ is sensitive to
Light intensity & colour
State the name of the coloured part of our eye that expands in bright light and contracts in dim light
Iris
State the name of the hole in the front of our eye that allows light in
Pupil
What happens to the size of the iris and pupil during bright light?
Pupil = small; Iris = big
What is the name for the light detecting cells at the back of the eye?
Retina
What happens to the eye during accommodation for focussing on near objects?
1) Ciliary muscles contract 2) Suspensory ligaments loosen 3) Lens is thick -> more refraction
What happens to the eye during accommodation for focussing on far objects?
1) Ciliary muscles relax 2) Suspensory ligaments pulled tight 3) Lens is thin -> less refraction
State the name for short sightedness
Myopia (focal point in front of retina)
State the name for long sightedness
Hyperopia (focal point past retina)
When amino acids are broken down by the liver, what is produced?
Amino acid -> ammonia (toxic) -> urea
What is the name for the process where amino acids are converted into ammonia?
Deamination
Where in the body are amino acids converted into ammonia?
The liver
Why is ammonia converted straight into urea?
Because it’s toxic
What is the name for the process where useful substances are reabsorbed from urine into the blood?
Selective reabsorption
What are the tiny tubes in the kidney called?
Tubules
Which hormone controls the water level in the body?
Antidiuretic hormone (ADH)
Where is the hormone that controls the water level in the body released from?
Pituitary gland
What happens to the amount of ADH released when there is too much water in the blood?
Very little ADH released
What happens to the amount of ADH released when there is too little water in the blood?
A lot of ADH released
Name a treatment for kidney failure?
Dialysis or transplant
What is the name of the blood vessel going into and out of the kidney?
In: Renal ARTERY; Out: Renal VEIN
What type of transport is used for water to be reabsorbed from the kidney tubules into the blood?
Osmosis
What type of transport is used for glucose/mineral ions to be reabsorbed from the kidney tubules into the blood?
Active Transport
Why is protein not filtered out of the blood by the nephron?
Too big
Which organ monitors and controls your blood glucose concentration?
The Pancreas
Which hormone is released if there is too much glucose in the blood?
Insulin
Which hormone is released if there is too little glucose in the blood?
Glucagon
Describe the effect of insulin in the body?
(Soluble) glucose stored in the muscle & liver cells as (insoluble) glycogen
Describe the effect of glucagon in the body?
(Insoluble) glycogen turned into (soluble) glucose and released from liver and muscle cells into blood
Describe what is wrong with a person if they have type one diabetes and how it is treated
Not producing enough insulin (genetic) -> treat with insulin injections
Describe what is wrong with a person if they have type two diabetes and how it is treated
Insulin not having an effect on the muscle/liver cells -> treat with controlled diet and exercise
State the hormones that are released from the pancreas and their effect on the body
Insulin - decreases blood glucose; Glucagon - increases blood glucose
Define ‘gland’
An organ that releases a hormone into the blood
Define ‘hormone’
A chemical messenger that travels in the blood to target organs
Define ‘negative feedback’ (higher tier only)
Our body’s way of monitoring changes in internal conditions and then responding to these changes so that homeostasis is regained
Which type of diabetes is inherited?
Type one
Which type of diabetes is caused by lifestyle?
Type two
How do glucagon & insulin travel around the body?
In blood
State a risk factor for type 2 diabetes
Obesity, Lack of exercise and sedentary way of life, High blood pressure, Family history, Aging
State the function of FSH (follicle stimulating hormone)
Causes egg to mature
State where FSH is produced
Pituitary Gland
State the hormone that FSH stimulates the production of (HT only)
Oestrogen from ovaries
State the effect of oestrogen
Causes uterus lining to build up
Which hormone inhibits FSH release? (HT only)
Oestrogen
Which hormone does oestrogen stimulate? (HT only)
Luteinising hormone (LH)
State the effect of luteinising hormone (LH) on the body
Causes ovulation
Where is luteinising hormone produced?
Pituitary Gland
Where is progesterone produced?
The empty egg follicle (corpus luteum)
State the role of progesterone
Maintains uterus lining; Inhibits FSH & LH.
Name 3 non-hormonal methods of contraception
Barrier method (diaphragm or condoms), abstinence, spermicide, sterilisation, some intrauterine devices.
Name 3 hormonal methods of contraception
Oral contraceptive pill, implant, injection, some intrauterine devices.
What does IVF stand for?
In Vitro Fertilisation (outside of the body).
What are the 4 stages of IVF? (Higher tier only)
1) Mother given FSH & LH to stimulate maturation of several eggs 2) Eggs collected from mother and fertilised by sperm in lab 3) Fertilised eggs develop into embryos 4) Two embryos inserted into mother’s uterus.
What is embryo screening?
Check embryo for genetic diseases and decide whether or not to use/abort the embryo.
What is the name of a plant’s response to (a) light (b) gravity (triply only)
(a) Light = phototropism; (b) Gravity = gravitropism/geotropism
Which plant hormone initiates seed germination? (triple only)
Gibberellins
Which hormone causes cell division and fruit ripening (triple only)
Ethene
State three uses of auxins
1) Weed killer 2) Rooting powder 3) Tissue culture
State one use of ethene
Controlling fruit ripening
State three uses of gibberellins
1) End seed dormancy 2) Promote flowering 3) Increase fruit size
When a shoot grows towards the light, what kind of tropism is demonstrated?
Positive phototropism
When a root grows away from the light, what kind of tropism is demonstrated?
Negative phototropism
When a root grows down (with gravity), what kind of tropism is demonstrated?
Positive geotropism
When a shoot grows up (against gravity), what kind of tropism is demonstrated?
Negative geotropism
How does auxin cause a shoot to grow towards light?
Auxin moves to shady side -> elongation of cells
How does auxin cause a plant to grow against gravity?
Auxin moves to lower side -> elongation of cells
State the names of 3 plant hormones
1) Ethene 2) Gibberellins 3) Auxin
Which transport method is used to move auxin from the tip of a plant to other parts?
Diffusion
Which part of a plant contains lots of new forming cells?
Meristem
