Energy for life

Question 1

what is cell respiration

Answer 1

The process of breaking down food molecules to release ATP

Series of chemical reactions

Question 2

Examples of uses of cells

Answer 2

Transporting molecules
Maintaining body temperature
Cell division
Contraction of muscle cells producing movement

Question 3

Aerobic respiration

Answer 3

Uses oxygen to break down glucose and release energy
Some energy is released as heat, but most is trapped in the form of ATP
Releases alot of ATP, completely oxidised solution

Question 4

Aerobic respiration equation

Answer 4

glucose + oxygen –> carbon dioxide + water

Question 5

Balanced aerobic respiration equation

Answer 5

c6h12o6 + 6o2 –> 6co2 + 6h2o

Question 6

Anaerobic respiration

Answer 6

Respiration without oxygen

Glucose not completely broken down, less ATP used

Question 7

Anaerobic respiration in fungi and plants

Answer 7

glucose -> ethanol + carbon dioxide

Question 8

Anaerobic respiration in animals

Answer 8

glucose -> lactic acid
occurs in muscle cells when low on oxygen
e.g. intensive exercise

Question 9

If lactic acid builds up…

Answer 9

…it causes cramps in muscles
Lactic acid sent to liver to be oxidised (disposed of)
Uses oxygen to dispose lactic acid

Question 10

Control variable

Answer 10

Something you keep the same

Question 11

Oxygen debt

Answer 11

Oxygen used to oxidise lactic acid

Question 12

Diffusion

Answer 12

Random movement of particles from a high concentration to a low concentration

Question 13

4 factors that affect diffusion

Answer 13

Temperature
Concentration gradient
Distance
Surface area

Question 14

Gas exchange process in humans

Answer 14

Air passes down trachea
Trachea splits to form 2 bronchi
Bronchi divide into bronchioles
Get to alveoli (site of gas exchange)

Question 15

What are the Trachea and Bronchi surrounded by?

Answer 15

C shaped rings of cartilage

Keep trachea open

Question 16

Pleural membrane

Answer 16

Double layer between lungs and thorax walls
Between membranes, thin layer of pleural fluid
Together form air tight seal

Question 17

Ribs

Answer 17

Help to protect the organs in the thorax

Intercostal muscles between ribs help connect bones

Question 18

Diaphragm

Answer 18

Seperating organs of thorax and abdomen

Domed sheet of muscle and fibrous tissue

Question 19

Ventilation

Answer 19

Process of moving air into and out of lungs

Relies in differences in air preasure between lungs and atmosphere

Question 20

Thorax

Answer 20

Upper part of the body

Question 21

Inhalation

Answer 21

Diaphragm contracts
Intercostal muscles contract
Volume of thorax now increases, air preasure decreases
Air in thorax less than atmospheric
This causes air to move into the lungs

Question 22

Exhalation

Answer 22

Diaphragm relaxes
Intercostal muscles relax
Causes air preasure of thorax to decrease and air preasure to increase
This causes air to move out of lungs

Question 23

Gas exchange occurs in what? What do they specialise in?

Answer 23

…alveoli

specialised for gas exchange

Question 24

Process of gas exchange

Answer 24

Oxygen diffuses from air into the red blood cells
Binds with haemoglobin for transport
CO2 dissolved in plasma diffuses from blood into alveolus

Question 25

What are alveolus surrounded by? Why?

Answer 25

Capillaries
Constantly carry deoxygenated blood to alveolus
Move oxygenated blood away
Maintains high concentration gradient (speeds diffusion)

Question 26

Why are the alveolus only 1 cell thick?

Answer 26

Gases only need to move a very small distance

Speeds diffusion

Question 27

Why does breathing rate increase when we exercise?

Answer 27

Increased concentration of CO2 in blood