biology

Question 1

How does diffusion and osmosis go in and out of the membrane?

Answer 1

Through passive transport

Question 2

How does proteins and carbohydrares get through the membrane?

Answer 2

Through active transport

Question 3

What is osmosis?

Answer 3

When water particles move from a high concentration to a low concentration through passive transport (doesn’t require energy).

Question 4

What is diffusion?

Answer 4

When molecules/particles move from a high concentration to a low concentration through passive transport (doesn’t require energy).

Question 5

Active transport

Answer 5

• requires energy to move substances
• uses ATP made during cellular respiration as the source of energy
• ATP powers the protein channel to open and let the substance move through
• happens fast
• low concentration to high concentration

Question 6

Passive Transport

Answer 6

• doesn’t require energy
• happens slowly
• high concentration to low concentration
• e.g. diffusion and osmosis

Question 7

Endocytosis

Answer 7

• The membrane pinches outwards to surround a particle which then rejoins together, connecting, leaving the particle inside a small sac made from the membrane called a vesicle.
• Phagocytosis is a version of endocytosis.
• Requires active transport to occur.

Question 8

Exocytosis

Answer 8

• Vesicle moves towards the cell membrane and sticks to it. The membrane joins together, releasing whatever was inside the vesicle out of the cell.
  This commonly occurs in the endocrine glands where they release hormones into the bloodstream.
• Exocytosis secretes and excretes particle out of the cell.
• Requires active transport to occur

Question 9

Phagocytosis

Answer 9

E.g. when a white blood cell absorbs infectious bacteria, germs, dead cells and fragments and engulfs it to be destroyed.
This is a mechanism where the cell eats particles.

Question 10

Surface Area to Volume Ratio

Answer 10

This is the reason why cells are so small.
The larger a cell gets, the surface area increases and volume increases but the ratio of surface area to volume decrease because the volume grows faster than the surface area.

Question 11

Autotrophs

Answer 11

• makes their own food
• plants

Question 12

Heterotrophs

Answer 12

• can not make their own food
• must eat from other living things
• animals, fungi and most bacteria

Question 13

Photosynthesis

Answer 13

• occurs in the chloroplast
• equation: carbon dioxide + water > glucose + oxygen
  Two stages:
  1. Light-dependent reaction (photolysis)
• chlorophyll captures solar energy to produce ATP
• takes place in the chloroplast
• PHOTOLYSIS occurs where the water and oxygen is split
  2. Light-independent reaction (Calvin Cycle)
• doesn’t need light as ATP provides energy
• combines carbon dioxide, hydrogen and ATP to produce glucose, water and ADP (adenosine diphosphate)
• takes place in the stroma

Question 14

Cellular Respiration

Answer 14

The opposite of photosynthesis:
Glucose + Oxygen > Carbon Dioxide + Water + ATP
- refers to the breakdown of glucose to make ATP
Two ways it can occur:
1. Aerobic respiration
2. Anaerobic respiration

Glycolysis occurs in both aerobic and anaerobic respiration. It’s the process where glucose is broken down into pyruvate.

Question 15

Aerobic respiration

Answer 15

Oxygen + Glucose > Carbon Dioxide + Water +ATP
-occurs in the mitochondria
- presence of oxygen
- Krebs cycle: pyruvate molecules moves into the mitochondria which then are broken down by oxygen to make carbon dioxide and water.
- 36 ATP molecules are gained

Question 16

Anaerobic Respiration

Answer 16

Glucose > ATP + Lactic Acid (animals) or ATP +Ethanol + Carbon Dioxide
- Occurs in the cytoplasm
- absence of oxygen
- 2 ATP molecules are gained
- Fermentation: this can be broken down into two separate way where alcohol or ethanol fermentation occurs in yeast and lactic acid occurs in animals.
- In alcohol/ethnaol fermentation the glucose is broken down into ethanol, carbon dioxide and ATP.
- In lactic acid the glucose is broken down to produce lactic acid and ATP. E.g. when your doing vigorous exercise, your muscles can’t catch up to the required energy needed to deliver enough oxygen.