Common q 1 ~

Question 1

How bacteria differ from other from other groups of organisms?

Answer 1

no nucleus (circular loop of DNA)
no mitochondria or chloroplast
celll wall of peptidoglycan

Question 2

State the function of nucleus.

Answer 2

stores genetic information

controls the activity of the cell

controls how cells divide

stores instructions for, protein synthesis

Question 3

State the function of cell membrane.

Answer 3

controls what goes in and out of the cell

separates the contents of the cell with its environment

Question 4

Explain what happens to the cell of a leaf cause wilting.

Answer 4

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.

Question 5

State features of diffusion that do not apply to active transport.

Answer 5

no energy or protein carriers;
substances move down a concentration gradient ;
does not have to occur across a membrane ;

Question 6

What is the benefit of having more fiber in diet?

Answer 6

stimulates peristalsis more than soft foods, less risk of constipation

Question 7

Describe the use of amino acids in plants.

Answer 7

used to make proteins for growth

Question 8

Explain how gravitropism enables a plant to survive

Answer 8

anchors plant, absorbs water and minerals between soil particles, to reach light, access to pollinators such as bees

Question 9

What are the symptoms of anaemia.

Answer 9

Not enough red blood cells. So tissues do not get enough oxygen delivered to them

Question 10

Describe the effects of diarrhoea on the body. (Cholera)

Answer 10

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.

Question 11

Explain why vitamin D is important?

Answer 11

helps calcium to be absorbed for making bones and teeth, prevents rickets

Question 12

Explain why iron is important?

Answer 12

for making haemoglobin, the red pigment in blood which carries oxygen,

prevents anemia

Question 13

Explain why vitamin C is important?

Answer 13

to make stretchy protein, collagen, found in skin and other tissues,

keeps tissues in good repair

Question 14

Describe the effects of vitamin D deficiency in humans.

Answer 14

rickets: bones become soft and deformed

Question 15

What is the function of canine?

Answer 15

piercing food and
killing prey (in carnivores)

Question 16

What is the function of molar?

Answer 16

grind food to increase their surface area

Question 17

Explain how villi are adapted for absorption.

Answer 17

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 ;

Question 18

Suggest why a protective substance (mucus) is necessary in the intestines.

Answer 18

help food slide easily through, prevent self-digestion

Question 19

Explain the advantages of coordinating the response to a dangerous situation
using both the nervous system and the endocrine system.

Answer 19

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.

Question 20

Describe the role of insulin in the body.

Answer 20

decreases blood glucose concentration

Question 21

Describe how blood glucose concentration can be lowered.

Answer 21

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.

Question 22

Explain how the nervous system differs from the endocrine system.

Answer 22

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

Question 23

State ways in which a voluntary action differs from an involuntary action

Answer 23

slower, think about actions, not automatic, learnt action, response to stimulus is not always the same

Question 24

Describe and explain the changes that occur in the eye when adjusting focus
from a distant object to a near object

Answer 24

ciliary muscles contract ;
suspensory ligaments become slack;
lens becomes fatter;
causing more refraction

Question 25

Outline the role of liver in excretion

Answer 25

1. Liver allows some to carry on in the blood, but excess is removed from the body.
2. Enzymes in the liver split up each amino acid molecule.
3. The energy-containing part is kept and turned into carb and stored. The nitrogen-containing part is turned into urea.
4. Urea dissolves in the blood plasma and is taken to the kidneys to be excreted
5. This process is called deamination!

Question 26

What do the kidneys remove?

Answer 26

excess water, excess ions, excess glucose and urea

Question 27

What is deamination?

Answer 27

the removal of the nitrogen-containing part of amino acids to form urea