Lipids, Proteins, Enzymes(LEC)

Question 1

are large molecules that increase the rates of chemical reactions without themselves undergoing any change

Answer 1

Enzymes

Question 2

Enzymes are extremely effective, increasing reaction rates by anywhere from __ to __ times

Answer 2

10^9 - 10^20

Question 3

refer to any group of organic molecules consisting of a basic amino group (-NH2), an acidic carboxyl group (-COOH), and an organic R group`

Answer 3

amino acids

Question 4

They are considered as the building blocks of proteins.

Answer 4

amino acids

Question 5

General Structure of amino acids

Answer 5

consists of a central carbon(C) atom, called the α-carbon, to which both an amino (-NH2) and a carboxyl group (-COOH) are attached, with an R group unique to the amino acid itself

Question 6

factors affecting enzyme activity

Answer 6

Temperature, pH, Enzyme concentration, Substrace concentration

Question 7

a phospholipid is considered amphipathic molecule if,

Answer 7

it contains that hydrophilic head and a hydrophobic tail

Question 8

beta oxidation process

Answer 8

1. Dehydrogenation catalyzed by acyl-CoA dehydrogenase, which removes two hydrogens between carbons 2 and 3.
2. Hydration catalyzed by enoyl-CoA hydratase, which adds water across the double bond.
3. Dehydrogenation catalyzed by 3-hydroxy acyl-CoA dehydrogenase, which generates NADH.
4. Thiolytic cleavage catalyzed beta-ketothiolase, which cleaves the terminal acetyl-CoA group and forms a new acyl-CoA, which is two carbons shorter than the previous one.

Question 9

There are two types of phospholipids:

Answer 9

Glycerophospholipids
Sphingolipids

Question 10

contain an alcohol, two fatty acids, and a phosphate group.

Answer 10

Phospholipids

Question 11

CLASSIFICATION OF LIPIDS BY FUNCTION

Answer 11

1. Lipids serve as a storage for energy
2. Lipids function as a membrane component of the cell.
3. Lipids also serve as chemical messengers.

Question 12

Cofactors may be:

Answer 12

Permanently attached, in which case they are called prosthetic groups.

• Temporarily attached coenzymes, which detach after a reaction, and may participate with another enzyme in other reactions.

Question 13

Permanently attached, in which case they are called prosthetic groups.
* Temporarily attached coenzymes, which detach after a reaction, and may participate with another enzyme in other reactions.

Answer 13

cofactors

Question 14

Cofactors can be:

Answer 14

organic molecules (coenzymes).
* inorganic ions (e.g. Ca, Zn).

Question 15

is known to induce plate aggregation. It is another derivative of arachidonic acid and is synthesized from prostaglandins (PGH2) but their ring is a cyclic acetal.

Answer 15

Thromboxane

Question 16

another substance that mediate hormonal responses. It is also derived from arachidonic acid, however, its structure has no ring closure.

Answer 16

Leukotriene

Question 17

They produce long-lasting muscle contractions, especially in the lungs, and can cause asthma-like attacks.

Answer 17

Leukotriene

Question 18

are fatty acid-like substances isolated from human seminal fluid. They are synthesized in the body by a ring closure

Answer 18

Prostaglandins

Question 19

good cholesterol

Answer 19

hdl

Question 20

bad cholesterol

Answer 20

ldl

Question 21

consists of about 33% protein and about 30% cholesterol

Answer 21

High-density lipoprotein (HDL)

Question 22

contains only 25% protein but 50% cholesterol

Answer 22

Low-density lipoprotein (LDL)

Question 23

mostly carries triglycerides (fats) synthesized by the liver

Answer 23

Very-low-density lipoprotein (VLDL)

Question 24

carry dietary lipids synthesized in the intestines

Answer 24

Chylomicrons

Question 25

is the most common and abundant steroid in the human body. It is mainly synthesized in the liver.

Answer 25

Cholesterol

Question 26

are another major class of lipids which contains ring structures composed of three cyclohexane rings and fused cyclopentane ring.

Answer 26

Steroids

Question 27

containing complex lipids with ceramide.

Answer 27

Glycolipids

Question 28

are components of the myelin, the coating of the nerve axon.

Answer 28

Sphingolipids is a phospholipid that is derived from sphingosine instead of glycerol in glycerophospholipids.

Question 29

is an amino alcohol that contains a long chain and unsaturated hydrocarbons.

Answer 29

Sphingosine

Question 30

refer to any group of organic molecules consisting of a basic amino group (NH2), an acidic carboxyl group (-COOH), and an organic R group

Answer 30

AMINO ACID

Question 31

Amino acids can exist in the _ and _ forms, where the are non-superimposable mirror images of each other (enantiomers). In almost all cases, amino acids are in the L-conformation.

Answer 31

d AND l

Question 32

In solutions, amino acids are ______ (can act either as an acid or a base) depending on the pH of the media.

Answer 32

amphoteric

Question 33

polymers of amino acids joined together by peptide or amide bonds

Answer 33

PEPTIDES

Question 34

explain the ketogenic diet

Answer 34

is a high-fat, adequate-protein, low-carbohydrate dietary therapy that in conventional medicine is used mainly to treat hard-to-control epilepsy in children. The diet forces the body to burn fats rather than carbohydrates.

Question 35

Lipids are long chains of repeating units of fatty acids and glycerol.

Answer 35

false

Question 36

Beeswax is a simple lipid.

Answer 36

true

Question 37

All other biomolecules are soluble in water except lipids.

Answer 37

true

Question 38

Lipids’ property of being insoluble in water makes it effective as a

a. storage form for energy

b. barrier between the external and internal cellular environments

c. chemical messenger

Answer 38

B

Question 39

What does being amphipathic mean?

Answer 39

possessing both hydrophilic and hydrophobic groups

Question 40

The shorter the chain and the more unsaturation a fatty acid has, the lower its boiling point is.

Answer 40

TRUE

Question 41

Cholesterol that’s transported through the bloodstream via LDLs is “good” cholesterol, while that transported via HDLs is “bad” cholesterol.

Answer 41

FALSE

Question 42

Leukotrienes, prostaglandins, and thromboxanes are all derived from

Answer 42

arachidonic acid

Question 43

The shorter the chain and the more unsaturation a fatty acid has, the more solid it is.

Answer 43

FALSE

Question 44

Which of the following lipids IS NOT found in animal cell membrane?

A. triacylglycerols
B. phosphoglycerides
C. cholesterol

Answer 44

triacylglycerols

Question 45

Fatty substances that do not contain fatty acids are not true lipids

Answer 45

FALSE

Question 46

In sphingolipids, glycerol is replaced by either glucose or galactose.

Answer 46

FALSE

Question 47

The shorter the chain and the more unsaturation a fatty acid has, the higher its boiling point is.

Answer 47

FALSE

Question 48

Not all lipids are made up of fatty acids.

Answer 48

TRUE

Question 49

Which is the correct sequence in beta-oxidation cycle? Refer to the list of events below and use their corresponding letters.

A - addition of water by a hydratase

B - dehydrogenation by FAD

C - dehydrogenation by NAD+

D - thiolytic cleavage by a thiolase

Answer 49

B A C D

Question 50

What are the immediate products per cycle of fatty acid beta-oxidation? Check only 3.

NADH
ATP
CO2
acetyl CoA
FAD
Coenzyme A
Water
FADH2
NAD+

Answer 50

NAPH
ACETYL COA
FADH2

Question 51

If a fatty acid with 16 carbons is completely oxidized in the beta-oxidation pathway, how many…

A - acetyl CoA are formed?

B - cycles of beta-oxidation will it have to undergo?

C - NADH will form?

Answer 51

8 acetyl CoA

7 cycles of beta-oxidation will it have to undergo?

7 NADH will form?