RESPIRATION + COMMUNICATION

Question 1

CELLULAR RESPIRATION

Answer 1

• breakdown of food (glucose) to release energy
• energy used to reform ATP
• occurs in several controlled steps
• in mitochondria

Question 2

CELL-CELL JUNCTIONS

Answer 2

• gap junctions

- connexins channels

Question 3

EXTRACELLULAR SIGNALLING JUNCTIONS

Answer 3

pannexin channels

Question 4

GAP JUNCTIONS

Answer 4

• plaque like structure
• formed from membrane proteins i.e. connexins
• allow for intercellular exchange of water, inorganic ions + small biomolecules (ATP, amino acids e.t.c.)
• integrate electrical + metabolic activities of cells

Question 5

GAP JUNCTION ROLES

Answer 5

• HEART (synchronisation of heartbeat)
• HEARING (recycling of K ions, maintaining endocochlear potential)
• SKIN (cell proliferation, differentiation, metabolism)
• VASCULAR CELLS (contraction of smooth muscle cells, signal transduction along endothelium)
• NERVES (action potential)

Question 6

INTERCELLULAR COMMUNICATION

FUNCTIONS

Answer 6

• coordinate diverse activities e.g. fight or flight response
• maintain homeostasis
• control growth of body

Question 7

HOW DO CELLS COMMUNICATE

Answer 7

• directly between adjacent cells (GAP JUNCTIONS)

- extracellular chemical messengers (PARACRINE, SYNAPTIC, ENDOCRINE)

Question 8

EXTRACELLULAR CHEMICAL MESSENGERS

Answer 8

• most common means of communication
• releasing + responding to chemical messages
• cells continuously talk to one another
• travel long or short distance to target cell
• bind to specific membrane receptor
• receptor activation triggers intracellular response

Question 9

PARACRINE SIGNALLING

Answer 9

• secreted by cell
• diffusing short distance to act on neighbouring cells
• e.g. inflammatory response

Question 10

SYNAPTIC - NEUROTRANSMITTERS

Answer 10

• released from nerve endings
• diffuse across short gap to act as chemical messengers on target cells
• target cell (plasma membrane of neurone, muscle or gland)

Question 11

ENDOCRINE SIGNALLING

Answer 11

• released from endocrine glands into bloodstream

- travels to target organ

Question 12

NEUROTRANSMITTERS VS HORMONES

Answer 12

• both specific
• hormones widespread (synaptic short)
• hormones slow but long lasting (synaptic rapid but short lasting)

Question 13

RESPIRATION STEPS

Answer 13

1. GLYCOLYSIS
2. TRANSITION REACTION
   (formation of acetyl co-enzyme A)
3. KREBS CYCLE
4. ELECTRON TRANSPORT CHAIN

Question 14

WHERE DOES GLYCOLYSIS OCCUR?

Answer 14

cytoplasm

Question 15

WHERE DOES KREBS CYCLE OCCUR?

Answer 15

matrix of mitochondria

Question 16

WHERE DOES ELECTRON TRANSPORT CHAIN OCCUR?

Answer 16

cristae of mitochondria

Question 17

NUMBER OF ATP PRODUCED IN ANAEROBIC RESPIRATION?

Answer 17

4 ATP

• 2 produced in glycolysis
• 2 produced converting pyruvic acid into lactic acid