Common q 1 ~ Flashcards
1-7, (10), 11-13, 15-16, (18), (19), 20 + chap 13
How bacteria differ from other from other groups of organisms?
no nucleus (circular loop of DNA)
no mitochondria or chloroplast
celll wall of peptidoglycan
State the function of nucleus.
stores genetic information
controls the activity of the cell
controls how cells divide
stores instructions for, protein synthesis
State the function of cell membrane.
controls what goes in and out of the cell
separates the contents of the cell with its environment
Explain what happens to the cell of a leaf cause wilting.
Rely on water for support.
1. Plant may lose more water from its leaves that it takes up from its roots.
2. Turgor pressure caused by water pushing outwards on the cell wall of plant cells decreases.
3. Individual cells lose so much water that they become soft and floppy, flaccid.
4. Tissues in the leaves are no longer supported by turgid cells pushing outwards against one another. The leaves become soft and floppy, flaccid.
State features of diffusion that do not apply to active transport.
no energy or protein carriers;
substances move down a concentration gradient ;
does not have to occur across a membrane ;
What is the benefit of having more fiber in diet?
stimulates peristalsis more than soft foods, less risk of constipation
Describe the use of amino acids in plants.
used to make proteins for growth
Explain how gravitropism enables a plant to survive
anchors plant, absorbs water and minerals between soil particles, to reach light, access to pollinators such as bees
What are the symptoms of anaemia.
Not enough red blood cells. So tissues do not get enough oxygen delivered to them
Describe the effects of diarrhoea on the body. (Cholera)
Large quantities of water is lost from the body in watery faeces. Death may occur without treatment due to dehydration and loss of chloride ions in the blood.
Explain why vitamin D is important?
helps calcium to be absorbed for making bones and teeth, prevents rickets
Explain why iron is important?
for making haemoglobin, the red pigment in blood which carries oxygen,
prevents anemia
Explain why vitamin C is important?
to make stretchy protein, collagen, found in skin and other tissues,
keeps tissues in good repair
Describe the effects of vitamin D deficiency in humans.
rickets: bones become soft and deformed
What is the function of canine?
piercing food and
killing prey (in carnivores)
What is the function of molar?
grind food to increase their surface area
Explain how villi are adapted for absorption.
microvilli provide a large surface area ;
epithelium, one cell thick to diffuse easily ;
secrete enzymes ;
good blood supply -> to maintain a steep concentration gradient ;
lacteal and fat transport ;
Suggest why a protective substance (mucus) is necessary in the intestines.
help food slide easily through, prevent self-digestion
Explain the advantages of coordinating the response to a dangerous situation
using both the nervous system and the endocrine system.
Nervous system responds rapidly. Impulses travel to effectors.
Effects of endocrine system lasts long. Hormones travel around the body and allows target organs to respond.
Less energy required since having to have nerves send impulses throughout tissues. More effective response due to using two systems.
Describe the role of insulin in the body.
decreases blood glucose concentration
Describe how blood glucose concentration can be lowered.
Islets on the pancreas detect increase in glucose concentration and secrete the hormone, insulin. This is an example of homeostasis.
Insulin reaches the liver causing the liver to absorb glucose from the blood. Some is used for respiration, but some is converted to glycogen which is then stored in the liver.
Explain how the nervous system differs from the endocrine system.
made up of neurones +
information transmitted in the form of electrical impulses = impulses carried along neurones
-impulses travel quickly so action is fast
-effect of impulse lasts a short time
State ways in which a voluntary action differs from an involuntary action
slower, think about actions, not automatic, learnt action, response to stimulus is not always the same
Describe and explain the changes that occur in the eye when adjusting focus
from a distant object to a near object
ciliary muscles contract ;
suspensory ligaments become slack;
lens becomes fatter;
causing more refraction
