Ch. 27, 2, 3 - Metabolism

Question 1

metabolism

Answer 1

all biochemical reactions in living organisms.

Question 2

Chemical reactions

Answer 2

occur when chemical bonds in existing molecular structures are broken and new bonds are formed. This is expressed as a chemical equation.

Question 3

Reactants

Answer 3

Substances present prior to start of a chemical reaction and written on left side of equation

Question 4

Products

Answer 4

substances formed by the reaction; written on right side of the equation.

Question 5

balanced equation

Answer 5

an equation where the number of elements are equal on both sides.

Question 6

Classification criteria for chemical reactions

Answer 6

1. changes in chemical structure
2. changes in chemical energy
3. whether the reaction is reversible or not

These determine what kind of chemical reaction occurred (decomp, synthesis, exchange)

Question 7

Decomposition reaction- catabolism

Answer 7

initial large molecule broken down into smaller structures. AB –> A + B

Question 8

Synthesis reaction- anabolism

Answer 8

two or more structures combined to form larger structure A + B –> AB

Question 9

Exchange reactions

Answer 9

Where two structures switch parts AB + CD –> AD + BC

Question 10

Carbs

Answer 10

structurally classified as mono, di, or polysaccharides. when describing dietary sources they are classified as sugars, starch, and fiber.

Question 11

Sugars

Answer 11

include the monosaccharides glucose, fructose, and galactose, and the disaccharides sucrose, lactose, maltose and dextrose.

Question 12

Sucrose dietary sources

Answer 12

table sugar, syrup, fruit

Question 13

Lactose dietary sources

Answer 13

milk sugar

Question 14

Maltose dietary sources

Answer 14

cereals

Question 15

Starch

Answer 15

polysaccharide polymer of glucose found in foods like tubers, grains, beans, and peas. Refined starches are sometimes used as thickeners like cornstarch.

Question 16

Fiber

Answer 16

Carb that includes fibrous molecules of both plants and animals and cannot be digested. Comes from lentils, peas, beans, whole grain, oatmeal, berries, nuts. Simulates peristalsis and lowers cholesterol.

Question 17

Glucose

Answer 17

6 carbon carb, most common monosaccharide and primary nutrient so level must be carefully maintained.

Question 18

Glycogen

Answer 18

liver and skeletal muscle store excess glucose and bind glucose monomers together (glycogenesis) and can also form glucose from noncarb sources (gluconeogenesis). Glycogen can be broken down via glycogenolysis.

Question 19

Hexose monosaccharides

Answer 19

glucose isomers (galactose, fructose)

Question 20

five carbon monosaccharides

Answer 20

pentose sugars; ribose and deoxyribose

Question 21

Lipids

Answer 21

fatty, water-insoluble molecules that function as stored energy, cellular membrane components and hormones. 4 main classes are triglycerides, phospholipids, steroids, and eicosanoids

Question 22

Triglycerides

Answer 22

used for long-term energy storage. Formed from glycerol and three fatty acids. Fatty acids vary in length and number of double bonds. Adipose tissue stores triglycerides

Question 23

Saturated fat

Answer 23

fatty acid that lacks double bonds

Question 24

Unsaturated fat

Answer 24

fatty acid that has one double bond. liquid at room temp. generally healthier.

Question 25

Polyunsaturated fat

Answer 25

fatty acid that has two or more double bonds. liquid at room temp and are found in certain oils such as soybean oil, corn oil, and safflower oil.

Question 26

Lipogenesis

Answer 26

formation of triglycerides when conditions of excess nutrients exist

Question 27

Lypolysis

Answer 27

breakdown of triglycerides when nutrients are needed.

Question 28

Phospholipids

Answer 28

amphipathic molecules that form chemical barriers of cell membranes. Has one end with a polar phosphate group such as glycerol, phosphate, or organic groups and form hydrophilic head and fatty acid group is nonpolar and forms hydrophobic tails.

Question 29

Steroids

Answer 29

Composed of hydrocarbons arranged in multi-ringed structure. There are 4 carbon rings, three have 6 carbon atoms and one has 5 carbon atoms. They differ in side chains extending from their rings. Includes Cholesterol, steroid hormones, and bile salts.

Question 30

Cholesterol

Answer 30

a steroid. component of animal plasma membranes and precursor to other steroid synthesis (steroid hormones, bile salts, vitamin d). Comes from diet or metabolic pathway in liver.

Question 31

Steroid hormones

Answer 31

testosterone and estrogen

Question 32

Eicosanoids

Answer 32

modified 20-carbon fatty acids synthesized from arachidonic acid (a membrane component). Primary functions include inflammation response and nervous system communication. Have four classes: prostaglandins, prostacyclins, thromboxanes, and leukotrienes.

Question 33

Most animal fats are...

Answer 33

saturated and solid at room temp.

Question 34

Most vegetable fats are...

Answer 34

liquid at room temp. and unsaturated. They tend to be healthier and can be converted to saturated fats through hydrogenation.

Question 35

Trans fats

Answer 35

partial hydrogenation of unsaturated fats. Increases the risk of heart attack and stroke.

Question 36

Cholesterol synthesis

Answer 36

synthesized by hepatocytes. Fatty acids are transported to liver and enter hepatocytes where they are broken down into two-carbon molecule called acetyl CoA through beta oxidation. Acetyl CoA turns into cholesterol using HMG-Coa reductase. Cholesterol is produced at basal level which varies among individuals and synthesis decreases with higher cholesterol intake.

Question 37

Cholesterol following synthesis

Answer 37

released into blood in very-low-density lipoproteins or synthesized into bile salts as part of bile.

Question 38

Bile salt reabsorption rate

Answer 38

90%. Other 10% is lost in feces.

Question 39

Transport of Lipids

Answer 39

VLDLs and LDLs are involved to transport lipids from liver to peripheral tissue.

Question 40

Very-low-density lipoproteins VLDLs

Answer 40

various types of lipids with protein. They are assembled within liver and released in blood. They circulate in blood and release triglycerides to peripheral tissues. They are primarily adipose tissue. After release of triglycerides, they become LDLs.

Question 41

Low-density lipoproteins LDLs

Answer 41

contain high amounts of cholesterol and deliver it to cells. Bind to LDL receptors in plasma membranes and are engulfed via endocytosis and the cholesterol is incorporated into the plasma membrane.

Question 42

High-density lipoproteins HDLs

Answer 42

Proteins formed in liver and released into blood without addition of lipid. They circulate the blood and fill with lipids from peripheral tissues. Like LDLs, HDLs also make cholesterol but it is not engulfed by cells. The lipids are then transported to the liver and excess cholesterol is converted to bile salts within liver.

Question 43

Blood Cholesterol Levels

Answer 43

High levels of LDLs or total cholesterol and low levels of HDL are a risk factor for cardiovascular disease. above 200 mm/dl is considered high. LDLs considered bad cholesterol because excess is deposited on inner arterial walls

Question 44

Liver Metabolic functions

Answer 44

carb, protein, and lipid metabolism, transport of lipids, storage, and drug detox.

Question 45

Proteins

Answer 45

most structurally and functionally diverse molecules needed to replace worn out protein structures in body. Amount needed depends on age (children need more) and sex, as well as injury, stress, and pregnancy. 8 amino acids are essential and the other 12 can be synthesized by body.

Question 46

How many amino acids are there

Answer 46

20. 8 cannot by synthesized.

Question 47

Protein functions

Answer 47

catalysts, defense, transport, support, movement, regulation, storage

Question 48

General Protein structure

Answer 48

one or more strands of amino acid monomers; each amino acid has an amine and carboxyl functional group both linked to the same carbon atom. That carbon is also covalently bonded to a hydrogen and different side chain structures called R groups. R groups distinguish aa's from one another. AA's are linked by peptide bonds.

Question 49

Peptide bond formation

Answer 49

formed during dehydration synthesis reaction between amine group of one amino acid and the carboxylic group of another. The H is lost from the amine group and the OH is lost from carboxylic acid.

Question 50

N- terminal end

Answer 50

end of polypeptide with free amine group

Question 51

C-terminal end

Answer 51

end of polypeptide with free carboxyl group.

Question 52

Oligopeptide

Answer 52

b/w 3 - 20 amino acids

Question 53

polypeptide

Answer 53

b/w 21 - 199 amino acids

Question 54

protein

Answer 54

more than 200 amino acids

Question 55

glycoproteins

Answer 55

proteins with carb attached. glycoproteins on erythrocytes determine ABO blood group.

Question 56

4 stages of cellular respiration

Answer 56

glycolysis, intermediate stage, citric acid cycle, electron transport system.

Question 57

glycolysis

Answer 57

anaerobic pathway occurring in cytoplasm. glucose is oxidized to 2 pyruvate molecules. 2 ATP and 2 NADH are formed. The pyruvate is converted to lactate if insufficient O2 is available.

Question 58

Intermediate phase

Answer 58

aerobic, in mitochondria. Pyruvate is converted to acetyl CoA and CO2 and NADH are formed.

Question 59

Citric acid cycle

Answer 59

acetyl CoA forms citric acid. CO2, ATP, FADH, and NADH are produced in each cycle.

Question 60

Electron transport chain

Answer 60

transfer of hydrogen and electron from NADH and FADH2. ATP formed through oxidative phosphorylation.

Question 61

Glycerol and Fatty acids in ATP production

Answer 61

glycerol enters pathway of glycolysis and is converted to glucose in liver. Carbons of fatty acids are removed to form acetyl CoA by beta oxidation and those molecules enter the citric acid cycle.

Question 62

amino acids and ATP production

Answer 62

may be used to generate ATP by removing the amine group by deamination. This occurs in liver hepatocytes and amine group is converted to urea and eliminated by kidneys. The remainder enters the metabolic pathway at different areas depending on the aa. It can enter glycolysis, intermediate, or citric acid cycle.