Definitions And Stuff To Memorise For Science

Question 1

Laws of reflection

Answer 1

1. Incident ray, reflected ray and the normal at the point of incidence all lie on the same plane.
2. Angle of incidence, i is equal to the angle of reflection, r.

Question 2

Properties of image from reflection

Answer 2

• It is laterally inverted.
• The perpendicular object distance is equal to the perpendicular image distance from the plane mirror.
• It is upright.
• It has the same size as the object.
• it is virtual.

Question 3

Acid + reactive metal = ?

Answer 3

Salt + Hydrogen gas

Question 4

Physical properties of acids.

Answer 4

• Sour taste
• Turns blue litmus paper red
• pH <7 ( smaller pH = more acidic solution)
• Conducts electricity when dissolved in water(in aqueous state)

Question 5

Test for hydrogen gas

Answer 5

• Effervescence occurred.
• Colourless odourless gas is produced.
• Gas extinguishes a burning lighted splint with a ‘pop’ sound.

Question 6

Acid + Metal Carbonate = ?

Answer 6

Salt + water + carbon dioxide

Question 7

Test for carbon dioxide

Answer 7

• Effervescence occurred
• Colourless and odourless has is produced
• Gas produced forms white precipitate in limewater

Question 8

Properties of Alkalis

Answer 8

• bitter taste and soapy touch
• turns red litmus paper blue
• pH >7 (larger pH = more alkaline solution)
• conducts electricity when dissolved in water

Question 9

Acid + base

Answer 9

Salt + water

Question 10

Alkalis + ammonium salt

Answer 10

Salt + water + Ammonia

Question 11

Test for ammonia

Answer 11

• Colourless and pungent has is produced

- gas produced turns moist/damp red litmus paper blue

Question 12

Indicators and their colours:

1. Litmus
2. Phenolphthalein
3. Methyl orange
4. Bromothymol blue
5. Universal indicator

Answer 12

In acidic solution—> in neutral solution—> in alkali solution

1. Red/__/ Blue
2. Colourless/colourless/ Pink
3. Red/Yellow/ Yellow
4. Yellow/Green/Blue
5. Red/Green/Purple

Question 13

Definition of isotope*

Answer 13

Isotopes are atoms of the same element with the same number of protons but different number of neutrons.

Question 14

What do amino acids consist of?

Answer 14

Carbon, hydrogen, oxygen and nitrogen.

Question 15

What does triglyceride consist of?

Answer 15

1 Glycerol and 3 fatty acids

Question 16

1. Monosaccharide

Answer 16

1.

• simplest form of carbohydrates
• Glucose is one of the most common monosaccharides
• glucose is substrate for respiration to release energy for all cell activities

Question 17

Polysaccharide

Answer 17

Types of polysaccharides

• Starch (Made and stored in plants but NOT ANIMALS)
• Glycogen (made and stored in animals and fungi but NOT PLANTS)
• Cellulose (to form supporting structure in plants e.g. cell walls)

Question 18

Definition of enzymes

Answer 18

Enzymes are biological catalysts. They speed up the rate of chemical reactions without themselves being chemically changed at the end of the reactions.

Question 19

Definition of digestion.

Answer 19

Digestion is the process that breaks down large, Insoluble, complex food substances into small, soluble, simple molecules that are small enough to be absorbed into the body cells.

Question 20

Digestion in mouth and enzymes produced

Answer 20

• Chewing, breaks up solid food into smaller pieces. This is a form of physical digestion.
• Salivary glands produce saliva which helps to moisten and soften the food to make it easier to swallow.
• Saliva contains salivary amylase which digests starch into maltose. This is chemical digestion.
• Tongue rolls the chewed up food into small balls. (bolus which is then swallowed)

Question 21

Oesophagus and peristalsis

Answer 21

• The bolus is moved along the oesophagus by peristalsis, which are wave-like contractions of the muscles to mix and propel the contents in the alimentary canal.
• no digestion is occured in the oesophagus, but digestion by salivary amylase in may continue.

Question 22

Stages in the menstrual cycle
Day 1 - 5 (menstruation)
Day 6 - 3 (Repair and growth of uterine lining)
Day 14 (Ovulation)
Day 15 - 28 (Further thickening of the uterine lining)

Answer 22

1 - 5.

• Low levels of oestrogen and progesterone.
• Uterine lining is shed out of body.

6 - 13.

• Oestrogen stimulates the repair and growth of the uterine lining.
• Uterine lining becomes Thick and spongy with blood vessels.

14.

• Release of mature ovum.
• usually starts 14 days before the start of the next menstruation phase.
• days before and after ovulation is called the fertile period

15 - 28

• Ovary secrets progesterone.
• Progesterone maintains and further thickens their uterine lining, which is ready for the embryo to be implanted.

Question 23

Pancreatic juice

Answer 23

- Stored in pancreas
Enzymes
-Pancreatic Amylase (starch—>glucose)
-Lipase (lipids—>fatty acids and glycerol)
-Trypsin (proteins—>polypeptides)

Question 24

Intestinal juice

Answer 24

-Stored in intestinal glands
Enzymes
-carbohydrases e.h. Maltase (maltose—>glucose)
-peptidase (polypeptides—>amino acids)
-lipase (lipids—>fatty acids and glycerol)

Question 25

Definition of fertilisation

Answer 25

Fertilisation occurs when the nucleus of a sperm (haploid) fuses with the nucleus of ovum (haploid) to form a fertilised egg called a zygote (diploid). Fertilisation takes place in the oviduct.

Question 26

Umbilical cord contains...

Answer 26

- Two umbilical arteries that transport deoxygenated blood and waste products form the fetus to the placenta. - One umbilical vein that transports oxygenated blood and nutrients from the placenta to the fetus.

Question 27

Mechanism of clotting

Answer 27

1. When there is a cut, platelets on the blood form a PLATELET PLUG by sticking to each other at the wound site. 2. The damage tissue and platelets will TRIGGER A SERIES IF ENZYMATIC REACTIONS THAT FORM A MESH (protein) which traps blood cells and bacteria. 3. As the blood clot it forms a SCAB. (Platelet plugs can’t stop bleeding for deep cuts effectively)

Question 28

Flow of blood through the heart

Answer 28

Step 1: both the Atria and Ventricles relax. Deoxygenated blood from all parts of the body enters the right atrium through the vena cat a while oxygenated blood enters into the left atrium through the pulmonary veins from both lungs. Step 2: Both Atria contract simultaneously (at the same time) while the ventricles relax, causing blood to flow into both ventricles. Step 3. Both ventricles contract while the atria relax.. Blood in the right ventricle will enter the lungs through the pulmonary arteries, while blood in the left ventricle will be pumped to the rest of the body though the aorta. Step 4. The cycle repeats.

Question 29

Advantages of double circulation.

Answer 29

1) blood enters the lungs at a lower pressure to Ensure that it flows more slowly through the lungs, allowing sufficient time for the blood to be well oxygenated before returning to the heart. 2) blood is pumped by the heart at a higher pressure to the rest of the body so that oxygenated blood is distributed to the body tissues more rapidly.