midterm study

Question 1

What are the four categories of enzymatic reactions?

Answer 1

1. Oxidation-reduction reactions.
2. Hydrolysis dehydration reactions
3. Addition-subtraction exchange reactions
4. Ligation reactions

Question 2

Describe the main ways that cells can regulate metabolism?

Answer 2

1. Controlling Enzyme concentration
2. producing modulators that change reaction rates
3. Using 2 different enzymes to catalyze reversible reactions
4. compartmentalizing enzymes within cellular organelles
5. Maintain an optimum ratio of ATP to ADP

Question 3

explain the basics of glycolysis?

Answer 3

• Does not require oxygen
• glycolysis takes place in the cytosol, 2 molecules of glyceraldehyde-3-phosphate (G3P) is formed for every glucose molecule (a total of 4 ATP is produced, a net gain of 2 ATP)

Question 4

How does the electron transport system worK?

Answer 4

• takes high energy electrons from NADH and FADH2
• energy is used to create ATP by creating an H gradient
• oxygen is the final acceptor of electrons and H to make h2o
• H concentrated between the two mitochondrial membranes
• the flow of H (down gradient) through ATP synthase in membrane results in a transfer of energy to make ATP

Question 5

describe the control of hormone release in the human body as a reflex pathway

Answer 5

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Question 6

Describe the main patterns of physiological communication

Answer 6

1. simple diffusion across small distances
2. Widespread distribution of molecules through the circulatory system
3. Rapid, specific delivery of messages by the nervous system

Question 7

what are the main classes of hormones?

Answer 7

1. Peptide/protein hormones
2. steroid hormone
3. Amine Hormones

Question 8

compare and contrast peptide and steroid hormones

Answer 8

peptide hormones are the most common hormones in the body, they are composed of linked amino acids and are water-soluble and lipophobic. While steroid hormones are derived from cholesterol and are lipophilic and hydrophobic

Question 9

describe the control of hormone release in the human body as a reflex pathway

Answer 9

• A stimulus is detected by a sensor, this sensor sends an afferent signal to the integrating center
• the integrating center is going to compile all the information it has received and send out an efferent signal to target tissues.
• the target tissues then initiate a response, when the response is achieved we seed a negative feedback loop to turn off signal

Question 10

List the anterior pituitary hormones. What are their functions?

Answer 10

1. Prolactin - Milk production & breast development
2. Luteinizing Hormone = sex hormones, ovulation
3. Adrenocorticotropic hormone - promotes the growth of the adrenal cortex
4. thyroid-stimulating hormone - stimulates the secretion of thyroid hormones & growth of thyroid gland
5. follicle stimulating hormone - stimulates growth and development of ovarian follicles
6. growth hormone - acts on body tissues

Question 11

What are the 3 basic patterns of endocrine pathology? Provide an example for each?

Answer 11

1. Excess
2. Deficiency
3. Abnormal responsiveness of target tissues

Question 12

Describe the route that a piece of food will take through your digestive tract and the main events that will occur in each place

Answer 12

1. Oral cavity - receives food, saliva helps to start the breakdown of food
2. Esophagus - muscular contractions move food through the thorax and into the abdomen
3. stomach - food gets mixed with acid and enzymes to make chyme
4. small intestine - where most digestion takes place
5. colon - chyme is converted to semi-solid feces
6. rectum - movement of feces into rectum triggers defecation reflex
7. anus - exit for feces

Question 13

explain the main stages of integrating GI function?

Answer 13

1. Cephalic Phase - the anticipation of food
2. Deglutition (swallowing) - going to push the bolus of food into the esophagus
3. Gastric Phase - consists of storage, digestion, and immune functions
4. Intestinal Phase - peristalitic contractions and segmental contractions move chyme along the tract

Question 14

How is glucose absorbed from the intestinal lumen?

Answer 14

Via a glut 2 transport protein, this occurs via secondary active transport

Question 15

explain how different macronutrients are digested and absorbed.

Answer 15

• Carbohydrates: must be broken down or digested before they can be absorbed
• Proteins: broken down into small peptides and amino acids by endo/exopeptidases
• Fats: digestion facilitated by bile salts

Question 16

What are the three types of reflexes in the regulation of GI function?

Answer 16

1. Long Reflexes
2. Short reflexes
3. Reflexes involving GI peptides

Question 17

what is the first law of thermodynamics?

Answer 17

energy cannot be created nor destroyed

Question 18

describe the factors that influence metabolic rate, and what their impact is

Answer 18

• Age (Decreases as we get older)
• Sex (Males > females)
• body composition (more muscle, less fat)
• activity level
• Diet (protein > fat)
• hormones
• genetics

Question 19

explain what is happening with all of the macronutrients when the body is in a fasted state

Answer 19

• Carbohydrates: glycogen in the liver is used for the entire body
• Proteins: can become energy sources when we are in extended fast (proteins can be used to produce ATP, or to make new glucose)
• Fats: broken down to glycerol

Question 20

Explain what is happening with all of the macronutrients when the body is in a fed state?

Answer 20

• Carbohydrates: glucose is the main source of energy for ATP production in fed state (absorbed in intestine)
• amino acids: taken to the liver by hepatic portal system
• Fats: used for energy and stored in adipose tissue

Question 21

what are the factors affecting insulin secretion? What are the functions of insulin?

Answer 21

1. Increase in plasma glucose
2. increase in plasma amino acids
3. feedforward effect of GI hormones
4. Parasympathetic activity
5. sympathetic activity

Insulin lowers blood glucose

Question 22

describe the interaction between insulin and glucagon

Answer 22

After a meal, insulin spikes and glucagon decreases. While after exercises, glucagon spikes, and insulin decreases

Question 23

Compare and contrast carbohydrate metabolism in the fed and fasted states.

Answer 23

in the fed state, glucose is the main source of energy for ATP production. in the fasted state, we get our energy from glycogen stores in the liver

Question 24

Compare and contrast lipid metabolism in the fed and fasted states.

Answer 24

In the fasted state lipids are broken down into glycerol, while in the fed state chylomicrons enter the blood via lymphatics

Question 25

Compare and contrast amino acid metabolism in the fed and fasted states

Answer 25

in the fed state, amino acids are taken to the liver by the hepatic portal system. in the fasted state ???

Question 26

Describe the factors affecting insulin secretion and describe its effects on the body once in circulation.

Answer 26

1. increase in plasma glucose
2. increase in plasma amino acids
3. feed-forward effect of GI Hormones
4. Parasympathetic activity - increased activity in GI tract and pancreas post-meal
5. sympathetic activity - inhibitory response

Question 27

Explain the potential metabolic outcomes of insulin deficiency.

Answer 27

can result in diabetes, chronic hyperglycemia

Question 28

Discuss in detail the body’s response to an increase in core temperature? What about a decrease?

Answer 28

Higher temperatures - speed up chemical reactions.

Lower temperatures - slow down chemical reactions