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Flashcards in 2. Macromolecules Deck (51)
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1

Macromolecules

Huge, highly organized molecules that form the structure and carry out the activities of cells

2

Macromolecules can be divided into four major categories

1. lipids
2. carbohydrates
3. nucleic acids
4. proteins

3

Carbohydrates, nucleic acids, and proteins are ______

polymers

4

polymers

composed of a large number of low-molecular-weight building blocks, or monomers

5

Lipids

a. small, diverse organic molecules that are insoluble in
H2O (polar) but soluble in nonpolar organic liquids
b.hydrophobic (water fearing) or contain significant hydrophobic regions

6

polar

different parts of the molecule have net negative or positive charge

7

micelle

an arrangement of lipids in water

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soluble

able to be dissolved, especially in water

9

Biological roles of lips (4)

a) source of NRG in the diet and serve to store NRG in the body
(eg. fats [solid] and oils [liquid])
b) some hormones (chemical messengers) are lipids
(eg. steroids and prostaglandins)
c) many vitamins
(eg. A, D, E)
d) the basic structural elements of biological membranes
(eg. phospholipids-lipid layer on outside, membrane bound)

10

Lipids:
FATTY ACIDS

-unbranched hydrocarbon chains with a carboxyl group at one end
-chains are typically 14 to 20 carbons
-chain is hydrophobic
-saturated(no double bonds)
-unsaturated(double bonds)
-carboxyl group is hydrophilic
-fatty acids are amphipathic
-they can form micelles in water- note how water is ordered around micelles (all in same orientation)

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amphipathic

both hydrophobic and hydrophilic

12

Carbohydrates

*have general formula (CH2O)n
*includes simple sugars (monosaccharides) and all larger molecules constructed of sugar building blocks

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monosaccharides

simple sugars
energy source and source of carbon

14

polysaccharides definition

very long chains of monosaccharide units
a) energy-storing molecules:
-glycogen in animals cells (usually stored in liver and muscle cells)
-every time a branch breaks off, that is a little bit of energy
-starch in plant cells - non branched

15

Structural polysaccharides:
Cellulose

-linear polymer of several 100-1000 glucose units
-an insoluble, rigid structural polymer
-makes up cell wall of plants
-plants have cellulase to break down cell wall in order to expand
-we cannot digest links between monomers of cellulose (the bonds differ from those of starch)
*we get no NRG from cellulose
*healthy fiber which helps move things along

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glycogen carbon chain is ______

branched

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starch carbon chain is ______

spiral

18

What species can digest cellulose?

cows and termites don't actually have cellulase (the enzyme that digest cellulose); it is their symbiotic bacteria and protozoa that digest cellulose

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Nucleic acids

polymers of nucleotides

20

nucleotides consist of three units:

1. nitrogenous base (ringed structured with N)
2. pentose sugar (5 C sugar)
3. phosphate group (PO4)

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nucleotides are attached to each other through the _________ backbone

sugar-phosphate

21

nucleotides are involved in 3 major cellular functions

1. nucleotides are monomeric units from which DNA and RNA are made (i.e. the molecules that encode the blueprints to life. Informations storage)
2. second messengers in cell signalling (eg. cAMP)
3. Agents of energy transfer for metabolism

22

nucleotides are agents of energy transfer for metabolism which does 2 things:

a. cleaving of phosphate groups releases energy (ATP)
b. Co-enzymes in energy transfer reactions (NAD)
(co-enzymes are non-protein compounds needed for enzyme action)

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NAD

nicotinamide adenine dinucleotide

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Ribonucleic acid (RNA)

- chain of ribonucleotides
-sugar is ribose (5 carbon ring)
-usually single stranded (not always)
even though it is single stranded, it can have 3 dimensional structure; it folds over and bases can pair with each other

25

RNA has 4 nitrogenous bases:

adenine
guanin
cytosine
uracil

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Deoxyribonucleic acid- DNA

-Chain of deoxyribonucleotides
-sugar is deoxyribose (O atom is missing at the C2 carbon) missing a hydroxyl group which RNA has
refer to slide 2 page 11

27

DNA has 4 nitrogenous bases

Adenine
cytosine
guanine
thymine (instead of uracil)

28

DNA is double stranded:

-DNA is a double-stranded helix
-two strands held together by H bonds between bases
-H bonds are between complementary pairs of purines and pyrimidines
-pairing rules: a-t
g-c

29

purines

adenine and guanine