Section C

Question 1

The three lipases and their roles:

Answer 1

Lingual lipase: Secreted by tongue, begins initial breakdown of triglycerides
Gastric lipase: Secreted by stomach, continues triglyceride breakdown in acidic environment
Pancreatic lipase: Secreted by pancreas, main enzyme for fat digestion in small intestine, breaks down triglycerides into fatty acids and monoglycerides

Question 2

Four steps in triglyceride absorption/transport:

Answer 2

1.Emulsification by bile salts
2. Formation of micelles
3. Absorption into intestinal epithelial cells
4. Repackaging into chylomicrons for transport via lymph system

Question 3

Final products of lipid digestion and pathways:

Answer 3

Fatty acids → β-oxidation pathway
Glycerol → converted to glyceraldehyde-3-phosphate, enters glycolysis
Monoglycerides → broken down to fatty acids and glycerol

Question 4

Three steps of fatty acid oxidation:

Answer 4

1. Activation (fatty acid + CoA → fatty acyl-CoA)
2. Transport into mitochondria
3. β-oxidation cycle (produces acetyl-CoA)

Question 5

Four reactions in chain elongation during lipogenesis:

Answer 5

1. Condensation
2. Reduction
3. Dehydration
4. Second reduction

Question 6

Role of HCl in protein digestion:

Answer 6

• Denatures proteins by breaking hydrogen bonds
• Activates pepsinogen to pepsin
• Creates acidic environment needed for pepsin activity

Question 7

Three protein digesting enzymes:
Pancreatic:

Answer 7

Trypsin: Breaks peptide bonds after basic amino acids
Chymotrypsin: Breaks bonds after aromatic amino acids
Carboxypeptidase: Removes amino acids from carboxyl end

Question 8

What is Nitrogen balance: with an example

Answer 8

State where nitrogen intake equals nitrogen output
Positive balance example: Growing children, pregnancy, muscle building

Question 9

List and briefly explain the three steps involved in removal of amino group during amino acid
degradation.

Answer 9

1. Transamination: Transfer of amino group to α-ketoglutarate
2. Oxidative deamination: Removal of amino group as ammonia
3. Transport of ammonia to liver for urea cycle

Question 10

Outline the fate of Ammonia, NADH and α-ketoglutarate produced during oxidative deamination

Answer 10

Ammonia enters urea cycle
NADH enters electron transport chain
α-ketoglutarate enters citric acid cycle

Question 11

Explain Negative nitrogen balance:

Answer 11

When nitrogen output exceeds intake, occurs during starvation or illness

Question 12

Outline the four stages of biochemical energy production pathways.

Answer 12

1. Digestion - Breaking down complex molecules into simple units
2. Acetyl group formation - Converting molecules to acetyl-CoA
3. Citric acid cycle - Oxidation of acetyl-CoA to CO2
4. Electron transport chain/oxidative phosphorylation - ATP production

Question 13

Identify the metabolic pathway each macromolecule will take to form the acetyl group

Answer 13

• Carbohydrates: Glycolysis → pyruvate → acetyl-CoA
• Lipids: β-oxidation → acetyl-CoA
• Proteins: Amino acid degradation → various intermediates → acetyl-CoA

Question 14

Briefly explain how the metabolic pathways of the macros are related to the common pathway

Answer 14

All pathways produce acetyl-CoA which enters the citric acid cycle, followed by the electron transport chain, forming the common final pathway for energy production.

Question 15

Identify where does the urea formation take place in the body and explain how it is eliminated from the body

Answer 15

Occurs in liver cells
Urea is transported via blood to kidneys and eliminated in urine

Question 16

List and briefly explain the four steps of urea cycle, clearly outlining the location of each step within
the cell

Answer 16

1. Carbamoyl phosphate synthesis (mitochondria)
2. Citrulline formation (mitochondria)
3. Argininosuccinate formation (cytosol)
4. Urea formation (cytosol)

Question 17

Outline any two (2) products formed during the carbon skeleton degradation of the amino acids and
explain how they are related to the metabolic pathways?

Answer 17

1. Pyruvate: Enters gluconeogenesis or forms acetyl-CoA
   2.α-ketoglutarate: Enters citric acid cycle directly

Question 18

Briefly outline the role of insulin on the metabolism of various macromolecules in the fed state

Answer 18

Carbohydrates: Stimulates glucose uptake, glycolysis, and glycogen synthesis
Lipids: Promotes fatty acid and triglyceride synthesis, inhibits lipolysis
Proteins: Increases amino acid uptake and protein synthesis

Question 19

G6P is an important intermediate of various carbohydrate metabolisms. What is the role of G6P
molecule during the fed state?

Answer 19

Acts as substrate for glycogen synthesis
Can enter glycolysis for energy production
Regulates glucose uptake through feedback inhibition
Can be converted to pentose phosphate pathway

Question 20

Name the major hormone that manages the fasting state metabolism.

Answer 20

Glucagon

Question 21

List the five (5) metabolic processes associated with the fasting state

Answer 21

Glycogenolysis
Gluconeogenesis
Lipolysis
β-oxidation
Ketogenesis

Question 22

Explain what is starvation and how does body get energy during starvation?

Answer 22

Starvation occurs when glycogen stores are depleted (>12-18 hours fasting). Body gets energy by:

Breaking down triglycerides for fatty acids
Converting amino acids from protein breakdown
Producing ketone bodies from excess acetyl-CoA
Using gluconeogenesis to maintain blood glucose

Question 23

Name the four organs that constitute our renal system

Answer 23

Kidneys
Ureters
Urinary bladder
Urethra

Question 24

For each of the organ that makes up the renal system, outline one function within the renal system

Answer 24

Kidneys: Filter blood, produce urine, regulate blood pressure
Ureters: Transport urine from kidneys to bladder
Urinary bladder: Stores urine temporarily
Urethra: Conducts urine from bladder to exterior

Question 25

For any two organs of the renal system, briefly describe its structure and location:

Answer 25

The kidneys: Bean-shaped organs approximately 10-12 centimeters long Located retroperitoneally at vertebrae T12-L3 Protected by the 11th and 12th ribs The urinary bladder: Hollow, distensible muscular organ Located in the pelvic cavity Positioned behind the pubic bone, anterior to the rectum

Question 26

Outline the two major portions of a nephron:

Answer 26

The renal corpuscle The renal tubule

Question 27

Briefly describe each structural portion of nephron outlined above:

Answer 27

The renal corpuscle: Contains a network of capillaries called the glomerulus The glomerulus is surrounded by Bowman's capsule Functions as the primary site of blood filtration The renal tubule: Consists of the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule Functions as the site of selective reabsorption and secretion Contains specialized epithelial cells for substance transport

Question 28

Outline the pathway that a drop of urine would travel from the collecting duct to the urethra:

Answer 28

The urine travels through: The collecting duct Through the papillary ducts Into the minor calyces Through the major calyces Into the renal pelvis Down the ureter Into the bladder Finally through the urethra

Question 29

List any four regulatory functions of the kidneys:

Answer 29

Regulation of blood pressure Maintenance of blood pH balance Control of blood volume Regulation of electrolyte balance

Question 30

Briefly explain any two regulatory functions of the KD

Answer 30

Regulation of blood pressure: Utilizes the renin-angiotensin-aldosterone system to regulate blood pressure Controls blood volume through selective water retention or excretion Adjusts sodium reabsorption to influence blood pressure Maintenance of blood pH balance: Selectively excretes or conserves hydrogen ions as needed Maintains appropriate bicarbonate levels in the blood Adjusts acid-base balance through controlled excretion

Question 31

Briefly outline any two internal features of renal parenchyma:

Answer 31

The renal cortex: Forms the outer region of the kidney Contains the majority of nephrons The renal medulla: Forms the inner region of the kidney Contains the renal pyramids

Question 32

List and define the three processes involved in urine formation

Answer 32

Glomerular filtration: The process where blood plasma is filtered through the glomerular capillaries into Bowman's capsule Creates the initial filtrate containing water, ions, and small molecules Tubular reabsorption: The selective reabsorption of useful substances from the filtrate back into the blood Includes reabsorption of water, glucose, amino acids, and important ions Tubular secretion: The active secretion of additional substances from the blood into the filtrate Includes secretion of excess hydrogen ions, potassium ions, and certain drugs

Question 33

What is micturition? Briefly explain the micturition reflex:

Answer 33

Micturition is the process of voiding urine from the bladder. The micturition reflex involves: Stretch receptors in the bladder wall are activated when the bladder fills Parasympathetic nerve signals trigger contraction of the detrusor muscles The internal and external sphincter muscles relax The process can be partially controlled through voluntary control of the external sphincter

Question 34

Name any four organs of the male reproductive system:

Answer 34

The testes The epididymis The prostate gland The seminal vesicles

Question 35

For each organ of the male reproductive system, outline two functions:

Answer 35

The testes: Production of sperm cells through spermatogenesis Production of testosterone and other male hormones The epididymis: Storage and maturation of sperm cells Transport of sperm from testes to vas deferens The prostate gland: Produces alkaline fluid that neutralizes acidic vaginal environment Secretes nutrients that support sperm survival The seminal vesicles: Produce fructose for sperm cell energy Secrete fluid that makes up approximately 60% of semen volume

Question 36

Name any two types of cells found in the testes and outline their function:

Answer 36

Sertoli cells: Support and nourish developing sperm cells Provide barrier protection for developing sperm Leydig cells: Produce testosterone Regulate male secondary sexual characteristics

Question 37

Define spermatogenesis:

Answer 37

Spermatogenesis is the process of formation and development of mature spermatozoa from primordial germ cells within the seminiferous tubules of the testes.

Question 38

Outline the four major stages of spermatogenesis:

Answer 38

Multiplication phase: Spermatogonia undergo mitotic division Produces more spermatogonia Growth phase: Primary spermatocytes form DNA replication occurs Maturation phase: Meiosis I produces secondary spermatocytes Meiosis II produces spermatids Transformation phase (spermiogenesis): Spermatids develop into mature spermatozoa Formation of acrosome, tail, and condensed nucleus

Question 39

Briefly outline the morphology of a mature sperm:

Answer 39

The mature sperm consists of: Head: Contains condensed nucleus with genetic material Acrosome with enzymes for egg penetration Midpiece: Contains mitochondria for energy production Provides power for sperm movement Tail: Flagellum for locomotion Propels sperm through female reproductive tract

Question 40

List four male reproductive organs that contribute to formation of semen:

Answer 40

The seminiferous tubules The seminal vesicles The prostate gland The bulbourethral glands

Question 41

Outline the composition of secretions from any two glands that contribute to formation of semen:

Answer 41

The seminal vesicles: Fructose-rich fluid Prostaglandins Fibrinogen Vitamin C The prostate gland: Citric acid Acid phosphatase Zinc Proteolytic enzymes

Question 42

Briefly describe the functions of secretions from the seminal vesicles and prostate gland

Answer 42

The seminal vesicles' secretions: Provide energy source for sperm through fructose Aid in sperm motility and survival The prostate gland's secretions: Neutralize acidic vaginal environment Support sperm viability and function

Question 43

List any four components of the reproductive duct system in men:

Answer 43

The seminiferous tubules The epididymal duct The vas deferens The ejaculatory duct

Question 44

For each of the four ducts of the male reproductive system, outline their function:

Answer 44

The seminiferous tubules: Site of sperm production Initial transport of immature sperm The epididymal duct: Storage of sperm Maturation of sperm cells The vas deferens: Transport of mature sperm Storage of sperm before ejaculation The ejaculatory duct: Combines sperm with glandular secretions Propels semen during ejaculation

Question 45

Briefly outline the passage of a sperm, as it moves through the ductus system from the seminiferous tubules to the urethra:

Answer 45

Sperm travels from: Seminiferous tubules → straight tubules → rete testis → efferent ductules → epididymis → vas deferens → ejaculatory duct → urethra

Question 46

Name any four organs of the female reproductive system:

Answer 46

The ovaries The uterine tubes (fallopian tubes) The uterus The vagina

Question 47

For each of the 4 main organs of the female reproductive system, outline two functions

Answer 47

The ovaries: Production of female gametes (oocytes) Secretion of female hormones (estrogen and progesterone) The uterine tubes: Transport of oocyte from ovary toward uterus Site of fertilization The uterus: Implantation and development of fertilized ovum Protection and nourishment of developing fetus The vagina: Passage for menstrual flow Birth canal during parturition

Question 48

Briefly describe the structure of Ovaries:

Answer 48

The ovaries are: Paired, almond-shaped organs located in the upper pelvic cavity Composed of: * Outer cortex containing ovarian follicles * Inner medulla with blood vessels and connective tissue * Covered by cuboidal epithelium and tunica albuginea

Question 49

Outline any two differences between oogenesis and spermatogenesis:

Answer 49

Number of gametes produced: 1. Oogenesis produces one functional ovum from one primary oocyte Spermatogenesis produces four functional sperm from one primary spermatocyte 2. Timing of completion: Oogenesis begins in fetal life and pauses until puberty Spermatogenesis begins at puberty and continues throughout life

Question 50

List the six phases of development in the primordial follicles:

Answer 50

1. Primordial follicle phase: Primary oocyte surrounded by single layer of follicular cells 2. Primary follicle phase: Development of zona pellucida Multiple layers of granulosa cells form 3. Secondary follicle phase Formation of antrum Development of theca cells 4. Mature follicle phase: Large antrum formation Complete development of corona radiata 5. Ovulation: Follicle rupture Release of secondary oocyte 6. Corpus luteum formation: Transformation of remaining follicular tissue Hormone production

Question 51

What is the fate of secondary oocyte after ovulation: After ovulation, the secondary oocyte can:

Answer 51

Be fertilized by sperm and complete meiosis II to form mature ovum If not fertilized within 24-48 hours, it will degenerate and be resorbed by the body

Question 52

Outline the four major parts of the uterus:

Answer 52

The fundus: Dome-shaped superior portion Located above the openings of uterine tubes The body: Main portion of uterus Contains the uterine cavity The isthmus: Narrow portion Located between body and cervix The cervix: Inferior portion Opens into vagina

Question 53

List the three layers of uterine walls:

Answer 53

The perimetrium (outer layer) The myometrium (middle layer) The endometrium (inner layer)

Question 54

Identify and briefly describe the structure of the layer of the uterus that sloughs off each month:

Answer 54

The functional layer (stratum functionalis) of the endometrium: Consists of simple columnar epithelium Contains spiral arterioles Rich in glands and connective tissue Responds to hormonal changes during menstrual cycle Completely shed during menstruation

Question 55

List the different parts of the uterine tube and briefly describe their structure:

Answer 55

The infundibulum: Funnel-shaped opening near ovary Contains finger-like projections called fimbriae Opens into peritoneal cavity The ampulla: Widest and longest portion Site of fertilization Contains mucosal folds and ciliated epithelium The isthmus: Narrow portion Thick-walled Connects to uterus

Question 56

What is ovulation:

Answer 56

Ovulation is: The process of releasing a mature secondary oocyte from the ovarian follicle Occurs approximately day 14 of a typical 28-day menstrual cycle Triggered by surge in luteinizing hormone

Question 57

Name two supportive ligaments of uterus:

Answer 57

The broad ligaments The round ligaments