Lecture 4

Question 1

What does a diversity of a biomolecule depend on

Answer 1

1.arrangement of carbon skeleton (can bond with other carbon atoms)
2. Other chemical groups

Question 2

What are the four types of biomolecules

Answer 2

1. Proteins
2. Nucleic acids
3. Carbohydrates
4. Lipids

Question 3

What is a polymer

Answer 3

Chain or ring of monomers (single unit)

Question 4

What type of reaction builds polymers

Answer 4

Dehydration/condensation

Question 5

What reaction breaks down polymers

Answer 5

Hydrolysis reactions

Question 6

Three functions of carbohydrates

Answer 6

1. Energy storage
2. Structural support and protection (plants and mushrooms)
3. Cell to cell recognition (immune function)

Question 7

What are the monomers of carbohydrates

Answer 7

Monosaccharides

Question 8

Carbohydrate is a general term for…

Answer 8

Sugar

Question 9

Polymers of carbohydrates

Answer 9

Polysaccharides

Question 10

Simple sugars (monosaccharides) have a C, H, O ratio of 1:2:1 like :

Answer 10

Glucose (C6H12O6), galactose, fructose…

Question 11

What bond connects monosaccharides

Answer 11

Covalent bond (formation of this bond is condensation reaction)

Question 12

When two monosaccharides linked together, cell wants store energy! Common disaccharides are :

Answer 12

Sucrose, lactose, maltose

Question 13

Store energy from polysaccharides

Answer 13

Starch (plants) and glycogen (animals)

Question 14

Glycogen is a highly branched polysaccharide stored in :

Answer 14

Liver and muscle cells

Question 15

Glycogen in liver :

Answer 15

Glucagon released by pancreas when blood sugar is too low. Glucagon makes liver break down glycogen to release glucose

Question 16

Glycogen in muscle cells

Answer 16

Glycogen stored for muscle cell itself

Question 17

Other storage polysaccharides in plants :

Answer 17

Cellulose

Question 18

Cellulose purpose

Answer 18

Protect themselves (plants)

Question 19

Human cannot digest cellulose bc

Answer 19

Can’t break bonds between b-glucose

Question 20

What is special about lipids

Answer 20

Not made of repeating monomers

Question 21

Lipids are defined by shared property :

Answer 21

Hydrophobic

Question 22

Three major types of lipids :

Answer 22

1. Fats (neutral fate)
2. Phospholipids
3. Steroids

Question 23

Functions of fats :

Answer 23

-energy storage
-insulation cold
-protection of internal organs

Question 24

Fat is constructed from smaller molcules

Answer 24

Glycerol and fatty acids

Question 25

Fatty acids molecule linked to glycerol by what reaction

Answer 25

Condensation/dehydration

Question 26

Triaglycerol :

Answer 26

Lipid used for E storage

Question 27

Saturated fatty acids have

Answer 27

Maximum nb of H atoms, no double bonds

Question 28

Unsaturated fats have

Answer 28

One or more double bonds

Question 29

Saturated FA structure

Answer 29

Bc form linear molecules -> easily stack, stabilizing molecules making them solid at room temp

Question 30

Unsaturated FA structure

Answer 30

Double bonds give them a kink -> don't stack well so liquid at room temp

Question 31

Our cells can break down unsat cis or unsat trans fat?

Answer 31

Cis (bc exists in enviro for long so cells have enzymes that metabolizes them)

Question 32

Trans fat resemble saturated fats bc

Answer 32

H atoms are diagonal opposite sides of double carbon bond -> more rigid and straighter than cis

Question 33

Why can't we break down trans fat

Answer 33

Bc artificial (food transformation) -> unnatural shape so not recognized by enzymes (accumulate in cell and tissues)

Question 34

Phospholipids functions

Answer 34

-major constituent of cell membrane -forms lipoproteins

Question 35

Phospholipids structure

Answer 35

-2 fatty acids -1 glycerol molecule -1 phosphate molecule

Question 36

Phospholipids are hydrophobic and hydrophilic?

Answer 36

Yes, hydrophobic tail (FA) hydrophilic head

Question 37

Steroids functions

Answer 37

-constituents of cell membrane (cholesterol -components of vitamins -components of hormones

Question 38

Steroids structure

Answer 38

-four fused carbon-ring molecules -diff differ in nb, position, composition of side chain

Question 39

How does cholesterol travel in blood

Answer 39

In lipoproteins

Question 40

Why is cholesterol in lipoprotein

Answer 40

Bc lipid -> hydrophobic and blood is mostly water

Question 41

LDLs (low density lipoproteins) are important for homeostasis bc

Answer 41

Cells have specific prot receptors that recognize prot on LDLs for cholesterol functions

Question 42

What happens if there's too much cholesterol

Answer 42

Excess is still in LDLs but not taken by cell -> circulate in blood

Question 43

Result of circulating LDLs

Answer 43

Higher risk of them sticking to vessel walls -> plaque that blocks blood vessels (arteries and arterioles)

Question 44

HDLs do what

Answer 44

Pick up excess LDL (and are synthesized by liver)

Question 45

What does liver do to LDL with HDLs

Answer 45

Specific prot receptor for prots found on HDLs -> removes excess cholesterol -> for digestion of fat or excreted in feces

Question 46

Result of high HDLs

Answer 46

Lower risk of cardiovascular diseases bc rid body of LDLs

Question 47

What is the sugar most found in blood/most common component of larger carbohydrates

Answer 47

Glucose