Alimentary

Question 1

Active transport of Na+ out of the cell with corresponding import of K+

1. consumes approximately ¼ of the bodies total energy expenditure
2. occurs via a symporter located in the plasma membrane
3. occurs at a greater rate than these ions pass back over the membran
4. is driven by potential energy created by an excess extracellular negative charge, resulting from active Cl- ion export.

Answer 1

1. consumes approximately ¼ of the bodies total energy expenditure

Question 2

Endocytosis delivers substances to endosomes and lysosomes, and

1. often relies on the presence of a protein coat which collects relevant occupied receptors into a pit
2. is always a chance event in which material is randomly taken up into vesicles at the cell surface
3. is used for the import of all material into cells
4. does not require energy input since it occurs down a concentration gradient and the forming of a vesicle is a spontaneous process

Answer 2

1. often relies on the presence of a protein coat which collects relevant occupied receptors into a pit

Question 3

The inherent free energy change of a reaction (DGf)

1. determines whether a reaction will be spontaneous or not
2. indicates the potential direction of a reaction under conditions of set concentrations of products and reactants
3. is decreased by the addition of a catalytic enzyme
4. becomes more negative, and the reaction becomes less likely, with increasing substrate levels
5. becomes more positive if the ratio of products to substrates increases

Answer 3

2. indicates the potential direction of a reaction under conditions of set concentrations of products and reactants

Question 4

Metabolism is controlled to reflect body conditions, mainly levels of food intake which affects the level of blood sugar. This control is mediated in part by

1. the ratio of products to substrates of metabolic pathways i.e. mass action
2. the release of hormones – namely glucagon and insulin – when blood sugar levels are high and low, respectively
3. allosteric mechanisms in which products tend to stimulate pathways

Answer 4

1. the ratio of products to substrates of metabolic pathways i.e. mass action

Question 5

Proteins that are secreted from cells are

1. often modified in the ER and Golgi with the addition of sugars, for example
2. translated from free ribosomes in the cytosol
3. transported to the cell surface and then released to the cell exterior through pores in the plasma membrane
4. taken up into secretory vesicles by an active translocation process which occurs after translation is complete

Answer 5

1. often modified in the ER and Golgi with the addition of sugars, for example

Question 6

A cross section of the GIT wall, from lumen to peritoneal surface, passes through the layers in which order?

1. epithelium, submucosa, lamina propria, circular smooth muscle, longitudinal smooth muscle, serosa
2. epithelium, serosa, submucosa, lamina propria, circular smooth muscle, longitudinal smooth muscle
3. epithelium, lamina propria, submucosa, circular smooth muscle, longitudinal smooth muscle, serosa
4. epithelium, submucosa, lamina propria, serosa, circular smooth muscle, longitudinal smooth muscle

Answer 6

1. epithelium, lamina propria, submucosa, circular smooth muscle, longitudinal smooth muscle, serosa

Question 7

The cephalic phase of gastric secretion:

1. is transmitted to the stomach by the parasympathetic nervous system, via the vagus nerve
2. decreases the rate of secretion of acid and pepsinogen from the stomach lining
3. is responsible for a decrease in acid secretion from gastric pits in response to low duodenal pH
4. is inhibited by parasympathomimetic drugs

Answer 7

1. is transmitted to the stomach by the parasympathetic nervous system, via the vagus nerve

Question 8

Why is it more difficult to swallow with the ventral aspect of the neck fully extended?

1. M. geniohyoideus pulls the hyoid rostrally.
2. M. sternohyoideus pulls the hyoid caudally
3. M. palatopharyngeus cannot contract
4. M. cricopharyngeus cannot contract
5. Epiglottis cannot close

Answer 8

2. M. sternohyoideus pulls the hyoid caudally

Question 9

Which germ layer(s) form the oral cavity and oral pharynx linings respectively?

1. Both endoderm.
2. Endoderm and ectoderm
3. Ectoderm and endoderm
4. Both ectoderm
5. Both mesoderm

Answer 9

3. Ectoderm and endoderm

Question 10

With which part of the nasal cavity do the paranasal sinuses communicate directly?

1. middle nasal meatus
2. dorsal nasal meatus
3. ventral nasal meatus
4. gutteral pouch
5. common nasal meatus

Answer 10

1. middle nasal meatus

Question 11

Which part of the mandible articulates with the temporal bone?

1. ramus
2. coronoid process
3. retroarticular process
4. symphysis
5. condylar process

Answer 11

5. condylar process

Question 12

The histological structure of the omasum of the ruminant stomach differs from other nonglandular compartments by possessing one of the unique histological features. Which one of the five features listed below best fits that unique characteristic?

1. extension of the lamina muscularis into laminae.
2. extension of the tunica muscularis into laminae.
3. the presence of papillae
4. the presence of keratinised stratified squamous epithelium.
5. the presence of a very thick tunica muscularis

Answer 12

1. extension of the lamina muscularis into laminae.

Question 13

Which of the following statements concerning chylomicrons is FALSE?

1. They contain mostly triacylglycerol with some cholesterol, phospholipid and protein
2. They are assembled inside intestinal cells
3. They are secreted directly into the blood
4. They contain triacylglycerol synthesised inside intestinal cells from monoacylglycerols and fatty acids
5. They enable fat soluble compounds to be transported in the blood

Answer 13

3. They are secreted directly into the blood

Question 14

Bile consists of bile salts, cholesterol, bile pigments and bicarbonate ions, along with other constituents. Identify the one statement that is correct.

1. bile salts and bile pigments are re-absorbed as part of the entero-hepatic circulation
2. bile salts and cholesterol aid in the absorption of fat-soluble vitamins
3. reabsorbed cholesterol forms part of chylomicrons which enter the blood in intestinal villi
4. the main effect of secretin is to induce gall bladder contractions whilst CCK increases HCO3- secretion from the bile duct

Answer 14

2. bile salts and cholesterol aid in the absorption of fat-soluble vitamins

Question 15

The enteric nervous system:

1. facilitates voluntary control of the gut via the myoenteric and submucosal plexuses
2. is modulated by the autonomic nervous system, with ACh generally inhibiting activity whereas noradrenaline is stimulatory
3. controls the release of gastrin from the stomach lining during the intestinal phase of gastric secretion
4. acts to initiate deglutition, elevating the tongue
5. receives efferents from the gut mucosa, which respond to stretch

Answer 15

5. receives efferents from the gut mucosa, which respond to stretch

Question 16

The hormones insulin and glucagon antagonise each other through regulating the phosphorylation status of key controlling enzymes of metabolism. Which one of the following statements is correct.

1. insulin acts on cell surface receptors to activate a protein phosphatise, which reduces phosphorylation of these key enzymes
2. the effect of phosphorylation of these enzymes is to increase their activity
3. glucagon binds to receptors on muscle cells to stimulate glycogen breakdown
4. the intracellular protein kinase, PKA, phosphylates key enzymes in response to insulin action

Answer 16

1. insulin acts on cell surface receptors to activate a protein phosphatise, which reduces phosphorylation of these key enzymes

Question 17

The reaction catalysed by pyruvate dehydrogenase (PDH) (pyruvate + CoA + NAD+à acetyl CoA + CO2 + NADH + H+) links glycolysis to the citric acid cycle. Predict which 3 of the following compounds would stimulate PDH activity.

Select one or more:

1. Pyruvate
2. acetyl CoA
3. Ca2+
4. ATP
5. Insulin
6. NADH

Answer 17

1. Pyruvate
2. Ca2+
3. Insulin

Question 18

The title oxidative phosphorylation arise because:

1. oxygen activates a protein kinase, PKA, which phosphorylates ATP synthase
2. oxygen accepts electrons from the electron transport chain, generating NADP from NAD+ + Pi
3. The oxidation of electron carriers pumps protons out of the mitochondrial matrix
4. The electrochemical proton gradient over the inner mitochondrial membrane is used to generate ATP from ADP + Pi by ATP synthase
5. oxidation of electron carriers is linked to ADP phosphorylation via the electrochemical proton gradient over the inner mitochondrial membrane

Answer 18

3. The oxidation of electron carriers pumps protons out of the mitochondrial matrix

Question 19

The protein thermogenin:

1. spans the ER membrane in brown fat cells
2. accelerates metabolic reactions, generating heat as a by-product
3. allows the free passage of K+ over membranes
4. is used to maintain body temperature in reptiles
5. generates heat through the movement of protons down their gradient

Answer 19

2. accelerates metabolic reactions, generating heat as a by-product

Question 20

Glycogen synthesis and breakdown are regulated in a reciprocal manner:

1. by the hormones glucagon and adrenaline
2. through allosteric effects on the key enzymes, phosphofructokinase and glycogen synthase
3. by opposing actions of protein kinases and phosphatases
4. through concurrent dephosphorylation of glycogen synthase and phosphorylation of phosphorylase

Answer 20

3. by opposing actions of protein kinases and phosphatases

Question 21

Glycogen deposits in muscle are broken down:-

1. in response to glucagon presence
2. to release glucose that buffer blood sugar levels
3. to provide fuel for short bursts of strenuous muscle activity
4. to power long distance flights of migratory birds

Answer 21

3. to provide fuel for short bursts of strenuous muscle activity

Question 22

The gluconeogenic pathway would be stimulated under all of the following conditions, except:

1. in an omnivore, between meals
2. in a carnivore, between meals
3. in a horse, after eating oats and chaff
4. in a ruminant, whilst ruminating
5. in a carnivore, shortly after a meat meal

Answer 22

3. in a horse, after eating oats and chaff

Question 23

Acetyl CoA levels increase in the liver during a fast for all of the following reasons, except:

1. the supply of fatty acids increases, generating more acetyl CoA from b-oxidation
2. the usage of acetyl CoA for fatty acids synthesis is decreased
3. the usage of acetyl CoA in the citric acid cycle is decreased
4. oxaloacetate decreases the activity of citrate synthase, the first enzyme of the citric acid cycle
5. gluconeogenesis decreases the level of oxaloacetate in the cells

Answer 23

4. oxaloacetate decreases the activity of citrate synthase, the first enzyme of the citric acid cycle

Question 24

Ketogenesis occurs in the liver of fasting animals, in response to increased acetyl CoA levels, for all of the following reasons, EXCEPT:

1. The relative deficiency of glucose stimulates gluconeogenesis, which depletes the citric acid cycle of intermediates
2. muscle-derived ketogenic amino acids are converted into acetyl CoA
3. the rate of b-oxidation in the liver falls, since the citric acid cycle is producing a lot of ATP
4. glucagon activates hormone-sensitive lipase, increasing fat mobilisation from adipose tissue, much of which is taken up and metabolised by the liver
5. glucagon inactivates acetyl CoA carboxylase, inhibiting fatty acid synthesis in the liver
6. b-oxidation is accelerated, so its reciprocal pathway (fatty acid synthesis) would be inhibited, through hormone action (glucagon)

Answer 24

3. the rate of b-oxidation in the liver falls, since the citric acid cycle is producing a lot of ATP

Question 25

Muscle metabolism is regulated by hormones, especially insulin versus adrenaline. All of the following statements are correct, EXCEPT:

1. muscle cells generally store glucose as glycogen when insulin drives the expression of GLUT4 glucose transporters to their cell surface
2. muscle cells take up glucose in large amounts when these transporters are expressed on the cell surface, under the influence of insulin
3. most muscle cells generate the majority of their energy from fatty acids metabolism, via b-oxidation and the citric acid cycle
4. resting and active glycolytic fast fibres generate much of their energy from glycolysis

Answer 25

4. resting and active glycolytic fast fibres generate much of their energy from glycolysis

Question 26

Propionate plays crucial roles in balancing the metabolism of ruminants. Which ONE function does it not perform.

1. Propionate can be metabolised to manufacture glucose, thus buffering blood sugar levels, albeit at a lower level than in other domestic species
2. this statement is correct – ruminants derive most of their glucose from metabolism of propionate
3. Propionate can be metabolised into amino acids, thus providing all essential mino acids to the ruminant.
4. Propionate can be metabolised into citric acid cycle intermediates, thereby promoting the use of acetate and butyrate to produce energy

Answer 26

3. Propionate can be metabolised into amino acids, thus providing all essential mino acids to the ruminant.

Question 27

3-OH butyrate, whether absorbed from the rumen or manufactured during ketogenesis, is used metabolically to produce energy via b-oxidation and the citric acid cycle in all of the following cells, EXCEPT:

1. cardiac myocytes
2. CNS neurones
3. erythrocytes
4. blood monocytes
5. kidney glomerular cells

Answer 27

3. erythrocytes

Question 28

cow is suffering with severe bloat after eating excessive amounts of lush pasture. She is recumbent and appears extremely unwell. Which of the following treatments would be most appropriate?

1. Drenching with a surfactant drug
2. Trochar and Cannula
3. Stomach Tube
4. Sitting the cow up into sternal recumbency
5. Sedating the cow

Answer 28

1. Drenching with a surfactant drug

Question 29

Trypsin prefers to break down peptide bonds with:

1. positively charged amino acids on the N terminal side.
2. large hydrophobic amino acids on the C-terminal side.
3. large hydrophobic amino acids on the N-terminal side.
4. positively charged amino acids on the C terminal side.
5. small hydrophobic amino acids on the N terminal side

Answer 29

1. positively charged amino acids on the N terminal side.

Question 30

Which of the following statements concerning the characteristics of glucose transport into intestinal cells is FALSE?

1. The process is competitively inhibited by galactose
2. Glucose and sodium are transported into the cell simultaneously
3. The process is saturable
4. Glucose and sodium are both transported up their concentration gradients
5. The Na+K+ ATPase inhibitor ouabain blocks the process

Answer 30

4. Glucose and sodium are both transported up their concentration gradients

Question 31

The reaction 2ATP à ATP + AMP occurs for all of the following reasons, except:

1. to generate an emergency source of energy (ATP) when the cells energy levels are low
2. to generate a signal (AMP) indicating low energy levels in the cell
3. to reduce the allosteric effect of ADP on regulated enzymes of glycolysis

Answer 31

3. to reduce the allosteric effect of ADP on regulated enzymes of glycolysis

Question 32

The cross sections of cranial canine duodenum can be clearly distinguished from the caudal duodenum by the following histological features. Which one of the following statements represents that distinctive feature?

1. The presence of villi
2. The presence of microvilli
3. The presence of Brunner’s glands
4. The presence of tunica muscularis
5. The presence of goblet cells

Answer 32

3. The presence of Brunner’s glands

Question 33

Ketogenic amino acids cannot be used to synthesise glucose BECAUSE:

1. they are metabolised via acetyl CoA, which is used up in the citric acid cycle
2. they are metabolised to pyruvate
3. they block the gluconeogenesis pathway
4. they are metabolised to acetyl CoA, which is always converted to ketone bodies
5. they are metabolised to succinyl CoA

Answer 33

1. they are metabolised via acetyl CoA, which is used up in the citric acid cycle

Question 34

Which of the following statements concerning the breakdown of fatty acids in mammals is FALSE:

1. The release of fatty acids for break down from triacylglycerol stored in adipose tissue is regulated by the hormones glucagon and insulin.
2. Fatty acids must be activated by the addition of Co-enzyme A before they can be broken down.
3. Fatty acyl CoA molecules are formed in the cytosol and cross the mitochondrial membrane before they are broken down.
4. In the β-oxidation pathway, fatty acids are broken down by the repeated removal of 2 carbon units as acetyl CoA in a cyclic process.
5. The energy obtained from 1g of triacylglycerol after the complete break down of the fatty acids is much greater than that obtained from 1g of glycogen.

Answer 34

3. Fatty acyl CoA molecules are formed in the cytosol and cross the mitochondrial membrane before they are broken down.

Question 35

Which one of the following metabolic pathways would NOT be stimulated in the liver of a carnivore after a typical meal:

1. glycogen deposition
2. gluconeogenesis
3. fatty acid synthesis
4. citric acid cycle
5. glycolysis

Answer 35

5. glycolysis