2. Macromolecules

Question 1

Macromolecules

Answer 1

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

Question 2

Macromolecules can be divided into four major categories

Answer 2

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

Question 3

Carbohydrates, nucleic acids, and proteins are ______

Answer 3

polymers

Question 4

polymers

Answer 4

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

Question 5

Lipids

Answer 5

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

Question 6

polar

Answer 6

different parts of the molecule have net negative or positive charge

Question 7

micelle

Answer 7

an arrangement of lipids in water

Question 8

soluble

Answer 8

able to be dissolved, especially in water

Question 9

Biological roles of lips (4)

Answer 9

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)

Question 10

Lipids:

FATTY ACIDS

Answer 10

• 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)

Question 11

amphipathic

Answer 11

both hydrophobic and hydrophilic

Question 12

Carbohydrates

Answer 12

• have general formula (CH2O)n

* includes simple sugars (monosaccharides) and all larger molecules constructed of sugar building blocks

Question 13

monosaccharides

Answer 13

simple sugars

energy source and source of carbon

Question 14

polysaccharides definition

Answer 14

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

Question 15

Structural polysaccharides:

Cellulose

Answer 15

• 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

Question 16

glycogen carbon chain is ______

Answer 16

branched

Question 17

starch carbon chain is ______

Answer 17

spiral

Question 18

What species can digest cellulose?

Answer 18

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

Question 19

Nucleic acids

Answer 19

polymers of nucleotides

Question 20

nucleotides consist of three units:

Answer 20

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

Question 21

nucleotides are attached to each other through the _________ backbone

Answer 21

sugar-phosphate

Question 21

nucleotides are involved in 3 major cellular functions

Answer 21

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

Question 22

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

Answer 22

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)

Question 23

NAD

Answer 23

nicotinamide adenine dinucleotide

Question 24

Ribonucleic acid (RNA)

Answer 24

- 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

Question 25

RNA has 4 nitrogenous bases:

Answer 25

adenine guanin cytosine uracil

Question 26

Deoxyribonucleic acid- DNA

Answer 26

-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

Question 27

DNA has 4 nitrogenous bases

Answer 27

Adenine cytosine guanine thymine (instead of uracil)

Question 28

DNA is double stranded:

Answer 28

-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

Question 29

purines

Answer 29

adenine and guanine

Question 30

pyrimidines

Answer 30

thymine and cytosine

Question 31

Overview of Proteins

Answer 31

- Consist of one or more polypeptide chains - a polypeptide is a polymer of amino acids linked together by peptide bonds - our cells may have as many as 10,000 different proteins - proteins have a diverse array of functions

Question 32

without co-enzymes, enzymes would work ________________.

Answer 32

very slow or not at all

Question 33

General functions of proteins (8)

Answer 33

1. enzymes- protein catalysts 2. structural elements- cytoskeleton=framework 3. contractile elements-movement 4. control activity of genes-genes being interpreted by proteins (transcription factors ) 5. transport material across membranes 6. carriers- bind to whatever its meant to carry, if available 7. hormones-insulin 8. antibodies

Question 34

Amino Acids

Answer 34

- building blocks of proteins | - organic acids that contain an amino group, carboxylic acid group and a R group

Question 35

R groups - amino acid side chains

Answer 35

R= side chain of variable structure =any of 20 different groups -difference is R groups account for different properties of amino acids and proteins

Question 36

R groups can be broadly classified as:

Answer 36

1. polar charged 2. polar uncharged 3. nonpolar 4. R groups with unique properties

Question 37

Structure of proteins

Answer 37

Primary structure secondary structure tertiary structure quaternary structure

Question 38

Primary structure

Answer 38

- the sequence of amino acids in a polypeptide - most polypeptides contain over 100 amino acids - in a polypeptide chain, amino acids are termed residues - amino acids joined by peptide bonds

Question 39

secondary structure

Answer 39

beta sheets or | alpha helices

Question 40

how to depict secondary structure

Answer 40

alpha helices are represented by helical ribbons beta sheets as flattened arrows connecting segments as thin strands

Question 41

tertiary structure

Answer 41

- The way that regions of secondary structure our oriented with respect to each other - predominates in globular proteins - tertiary structure results from side chain interactions

Question 42

van der waals forces

Answer 42

In physical chemistry, the van der Waals forces (or van der Waals' interaction), named after Dutch scientist Johannes Diderik van der Waals, is the sum of the attractive or repulsive forces between molecules (or between parts of the same molecule) other than those due to covalent bonds, or the electrostatic interaction of ions with one another, with neutral molecules, or with charged molecules.[1] The resulting van der Waals forces can be attractive or repulsive.[2] The term includes: force between two permanent dipoles (Keesom force) force between a permanent dipole and a corresponding induced dipole (Debye force) force between two instantaneously induced dipoles (London dispersion force).

Question 43

Side chain interactions are

Answer 43

Hydrogen bonds hydrophobic bonds ionic bonds disulfide bonds (covalent between two cysteines) (non covalent bond takes little NRG to break, therefore are weak)

Question 44

quaternary structure

Answer 44

-multimeric proteins contain several polypeptide subunits -often the subunits can be independently folded -quaternary structure is the spatial arrangement of these subunits (slide 2 page 21)

Question 45

why is protein structure important?

Answer 45

a protein structure determines its function

Question 46

Tertiary and quaternary structures can be determined using __________and _________.

Answer 46

x-ray crystallography | nuclear magnetic resonance

Question 47

subtle changes in a protein's structure can have a _____ impact on on its ability to ____________ its function within the cell.

Answer 47

huge | perform

Question 48

Cell _______ modify _________ structures to regulate _________.

Answer 48

routinely protein activities

Question 49

_________can be (are not always) damaging to the proteins structure.

Answer 49

mutations

Question 50

a changed amino acid can alter a protein's ability to_______________________.

Answer 50

interact with other molecules