Biology cram 1

Question 1

What do alpha cells secrete?

Answer 1

Glucagon

Question 2

What do Beta cells secrete?

Answer 2

Insulin

Question 3

How is blood glucose levels increased?

Answer 3

Ingestion of food and drink w/ carbohydrates

Question 4

How is BGL decreased?

Answer 4

Following exercise

Question 5

BG regulation process

Answer 5

Pancreas detects change in BGL, Insulin/Glucagon released to bring BGL back to normal

Question 6

How is Insulin secreted?

Answer 6

At normal BGL, K+ channels of Beta cells are open so maintain a -70 mV resting potential

If BGL rise, glucose enteres the cell through a glucose carrier, this makes ATP and binds to K+ channels causing depolarisation

Forces Ca2+ channel to open, causing insulin exocytosis

Question 7

How does Glucagon increase BGL

Answer 7

Attaches to receptors, causes cAMP activation, cAMP activates protein kinase, hydrolyses glycogen into glucose

Question 8

What is Glycogenesis

Answer 8

Glucose conversion to glycogen (stores energy and reduces blood sugar) (Promoted by insulin)

Question 9

What is Glycogenolysis?

Answer 9

Glycogen conversion to glucose (promoted by Glucagon)

Question 10

Gluconeogenesis?

Answer 10

Producing glucose from non carbohydrate substrate

Question 11

Why is gas exchange in fish effective?

Answer 11

Large SA
Short diffusion distance
Maintain concentration gradient

Question 12

What is the counter current flow mechanism?

Answer 12

Water flows over gill lamellae in opposite direction of the blood

Question 13

Why is insect gas exchange system effective?

Answer 13

Large SA: Many branching tracheols
Short diffusion distance: Tracheols reach muscle + thin walls
Maintain concentration gradient

Question 14

Protein synthesis

Answer 14

Protein bound to RER, passes into cisternae and gets packaged into transport vesicles
Move to golgi aparatus and fuse, vesicles carry

Question 15

Transcription

Answer 15

DNA helicase breaks down hydrogen bonds between DNA

Free mRNA nucleotides align opposite exposed complementary DNA

RNA Polymerase joins together RNA nucleotides

Question 16

How is CO2 transported in the blood

Answer 16

Dissolved in blood plasma as haemoglobinic acid

Reacts w/ amino acids to form haemoglobinic acid

In the cytoplasm of RBC, hydrogen carbonate ions formed

Water and CO2 react, forming H+ and HCO-
Carbonic acid diffuses out of the RBC and Cl- diffuses into RBC

Question 17

Physical responses to herbivory from plants

Answer 17

Thorns, stings, fibrous inedible leaves

Question 18

Chemical Responses to herbivory

Answer 18

Tannis, Alkaloids, terpenoids

Question 19

What are plant responses to abiotic stress

Answer 19

Leaf loss
Day light sensitivity
preventing freezing
Stomatal control

Question 20

Plant hormones

Answer 20

Auxin: controls cell elongation, Apical dominance
Ethene: Ripenning of fruit
Gibberellins: Stimulate seed germination
ABA: Stimulate stomatal closing

Question 21

Brain structure

Answer 21

Cerebrum: Conscious thought
Cerebellum: Movement, muscles
Medulla: Unconscious activities
Hypothalamus: Homeostasis
Pituitary gland: Hormone secretion

Question 22

Fight or flight response:

Answer 22

Autonomic nervous system detects the potential threat, sends impulse to hypothalamus to adrenal glands, release adrenaline and noradrenaline

Question 23

Pacinian corpuscle

Answer 23

Pressure applied –> membrane deforms –> Na+ channels widen and Na+ diffuses in –> establishes a generator