General Revision Flashcards
How does the eye focus on near objects? How does it adjust to distant objects?
To look at near objects, the ciliary muscles contract which slackens the suspensory ligaments - this increases the curvature of the lens. This means that the light is refracted more. To look at distant objects, the ciliary muscles relax - reducing the curvature of the lens and reducing the amount that light is refracted.
What is the sclera?
The sclera is the tough outer layer of the eye, in between the socket and the eye.
What is the cornea?
The cornea is the layer between the conjunctiva and the pupil. It refracts light onto the lens and prevents us damage to the eyes.
What is the retina?
The retina is the area at the back of the eye where photo receptors are.
What is the iris?
The iris is the part of the eye that controls the diameter of the pupil.
What are the radial muscles?
The radial muscles control the size of the pupil - by increasing and decreasing the size of the iris.
What happens to the eye when it adapts to a bright light?
The radial muscles relax - thus allowing the iris to grow (meaning that the the pupils is smaller and lets less light in…)
How does one test for the presence of lipids in a food sample.
Add the sample to a test tube, add ethanol, shake and if there is an emulsion lipids are present.
What is a protoctist?
A protoctist is any uni cellular organism that is not a fungi.
What are multi-cellular fungi made up of?
They are normally made up of thread-like structures named hyphae.
Give an example of a disease caused by a protoctist and the name of the protoctist.
Malaria - which is caused by the protoctist ‘plasmodium’
Which of bacteria, fungi and viruses have cell walls?
Bacteria and fungi have cell walls
Describe a reflex arc for responding to touching a hot object.
A temperature receptor [1] registers the heat. This sends an impulse through the sensory neurone [1] to the spinal cord [1]. The brain then sends a response. A relay neurone [1] then passes this to the motor neurone[1], it then goes to the effector[1], which contracts [1] moving the finger away from the heat.
Give three reasons why viruses aren’t considered living.
They cannot reproduce without a host.
They cannot move.
They cannot grow.
How do bacteria store their DNA
Bacteria store their DNA in plasmids - not in the nucleus
How are villi adapted to absorb glucose.
Villi have high surface areas, due to the micro villi. The microvilli are connected to capillaries so that the glucose can be moved away and the concentration gradient remains favorable - so that diffusion happens. The microvilli are one cell thick - so glucose can diffuse across.
What colour does a negative result for glucose give with Benedict’s solution test?
Blue
How does one test for protein?
Add biuret’s solution to the sample and if it is present the sample will turn purple.
Give an example of a Fungi
Mucor
What does CORMMSS stand for?
C- Changing
O- what organism
R - repeat
M1- measure dependent variable
M2- Timescale for DV
S1 What is kept the same
S2 What is kept the same
What should be in a diagram of a phagocyte?
The cell membrane, the nucleus and the cytoplasm.
All three should be labeled.
Look at leaf diagram in photo
Look at diagram of respiratory system
What colour does Hydrogen-Carbonate indicator turn in high levels of Co2.
In high levels it turns orange, in normal levels it turns yellow, in low levels it turns purple
Which cells contain chlorophyll in plants?
Chloroplasts
Which parts of the body is faeces stored in and expelled from?
Faeces is stored in the rectum and expelled from the anus.
What is egestion? How does it differ from excretion?
Egestion=defecation
Egestion expels faeces instead of a metabolic waste product (e.g co2 or urea)
Egestion takes place at the anus not in the lungs/skin/kidney
How is the spongy mesophyll layer adapted for Photosynthesis?
Spongy mesophyll cells are covered by a thin layer of water, which gases dissolve into. When the plant is photosynthesising, this allows co2 to diffuse into cells and oxygen to diffuse out.