biochemistry

Question 1

What are the 4 functional groups and what do they do?

Answer 1

OH (hydroxyl) - in carbohydrates and alcohols
COOH (carboxyl) - fatty acid/and in amino acids
NH3 - amino group
PO4 (phosphate) - in nucelic acids

Question 2

What is a condensation reaction?

Answer 2

When organic molecules are bonded and water is a byproduct (water in released during the reaction) also known as dehydration
(to undo hydrolysis/add water)

Question 3

What are the different proteins structures?

Answer 3

Primary - sequence of AAA
Secondary - some repel some attract (alpha helix and beta pleat)
Tertiary- 3D arrangement of secondary structure (cuz of bonds)
Quaternary - 2+ polypeptides combined (may or may not happen)

Question 4

Types of covalent bonds (2)

Answer 4

Non polar: sharing electrons evenly - hydrophobic/lipophillic
Polar: sharing elections unevenly (overall charge) - hydrophilic/lipophopic

Question 5

Life is _________ based

Answer 5

Carbon

Question 6

What is “the ability to take away e from other atoms?

Answer 6

Electronegitivity

Question 7

Uses of carbohydrates (and some sources?)

Answer 7

Uses: energy, plant cell walls, exoskeleton of insects, etc.
Sources: bread, grains, potatoes, sugars, cellulose, etc.

Question 8

Uses of proteins? (7)

Answer 8

Structure (nails, collagen, bones, hair)
Muscle (movement)
Transport of o2 (hemoglobin)
Hormones
enzymes
Cell communication
Antibodies

Question 9

Differences and similarities between cellulose and starch?

Answer 9

Both are polysaccharides

Cellulose:
- energy storage in plants
- beta 1,4 glycosidic bonds
-monosaccharides flip each time (cuz of shape)
Starch:
- energy storage in animals
- alpha 1,4 glycosidic bonds

Question 10

saturated fats vs unsaturated fats (cis vs trans)

Answer 10

saturated: all carbons are connected by single bonds (very dense - you can stack them together/solid at room temp)

unsaturated (essential for humans): contain at least 1 double bond between carbons (liquid at room temp)
- cis : both hydrogen atoms located on the same side of double bond
- trans fatty acids have the two hydrogen atoms on opposite sides of double bond

Question 11

denaturation of h bonds (explain)

Answer 11

heat or extreme cold can break h-bonds which alters the structure of the protein/enzyme/etc. the proper function may not be achieved if this is the case
(denaturation can also be caused by bases, acids or lots of salt)

Question 12

enzymes (structure, function)

Answer 12

enzymes are organic catalysts that facilitate chemical reactions. a substrate is anything an enzyme works on and therefore they have a shape the is specific to their substrate (induced fit)

allosteric site: on/off switch
active site

Question 13

how are enzymes regulated (4)

Answer 13

competitive inhibition: compete for active site (other substrate with similar shape, high concentration)

non comp inhibition: does not invovle the active site
- allosteric: allosteric site (shape change)
- feedback; high levels of product has backward effect (inhibits enzyme that catalysts the first or one of the first reactions in a series)

Question 14

enzyme optimum is based on two factors?

Answer 14

pH (ex. pepsin has pH optimum 1-2)
temperature (so that enzyme has right shape)

Question 15

what is a phospholipid?

Answer 15

glycerol + Pi (& R group) + 2 fatty acids
hydrophilic end: glycerol + Pi (& R group: variable attachement)
hydrophobic end: fatty acids
- make up cell membrane

Question 16

what are the names of the bonds in carbohydrates, lipids and between AA in a protein?

Answer 16

carbohydrates: gylcosidic bonds
lipids: ester bonds (between fatty acid and glycerol)
proteins: peptide bonds

Question 17

triglyceride?

Answer 17

three fatty acids bond (thru condensation reactions) to a glycerol

Question 18

shape of all the macromolecules?

Answer 18

carbohydrates:
- monosaccharides: 1 carbon based ring
- disaccharides: 2 monosaccharides
bonded by a condensation reaction
- polysaccharides: many monosaccharides bonded (thousands)
lipids: triglyceride - glycerol bonded to three fatty acids (long chains)
proteins: amino acids covalently bonded to form polypeptides

Question 19

where does energy come from in lipids (why are they so energy rich)

Answer 19

they have many h-c bonds (hydrocarbons)

Question 20

why are lipids important?

Answer 20

insulation
cell membrane (phospholipids)
cushioning (ex. kidney, butt)
sebum
energy storage
hormones (steroids: estrogen + testosterone)
cholesterol: keeps cell membrane at right fluidity

Question 21

amino acids?

Answer 21

monomer for proteins
20 common ones (8.5 are essential)
non polar/polar (therefore they repel/attract)

amino group - NH3 + R group - variable attachement + COOH - carboxyl

Question 22

enzyme naming?

Answer 22

suffix - ASE
prefix - what it works on
(ex. lactase)

Question 23

cofactors vs coenzymes

Answer 23

cofactors: inorganic activators/inhibitors (minerals)
coenzymes: organic activators/inhibitors (carbon based - ex. vitamin c)

Question 24

label cell diagrams and explain the functions of the organelles

Question 25

cell membrane
+ diagram

Answer 25

semi permeable, cell communication, phospholipid bilayer, small nonpolar diffuse across

carrier, protein attachments, phospholipid bilayer (hydrophilic heads, hydrophobic tails), peripheral protein, cholesterol (fluidity), transmembrane protein

Question 26

types of passive transport

Answer 26

diffusion: along concentration gradient
osmosis: diffusion of H2O
facilitated diffusion: diffusion of larger molecules across cell membrane with the help of proteins
- carrier proteins: larger molecules: glucose, AA
- channel proteins: ions of small polar molecules

Question 27

what is active transport

Answer 27

transport AGAINST a concentration gradient… ATP is needed

Bulk transport
- Endo/exocytosis (often receptor mediated)
- for endocytosis pinonvs phago
Co transport

Question 28

what happens to animal vs plant cells in different solutions

Answer 28

Animals
HYPERTONIC: cells will shrivel (crenation)
ISOTONIC: no change
HYPOTONIC: cells will swell and even burst - lysis

Plants
HYPERTONIC: central vacuole shrinks, cell becomes flaccid (plasmolysis)
ISOTONIC: slightly flaccid
HYPOTONIC: deplasmolysis: when cell becomes turgid and vacuole presses against cell wall)

Question 29

water potential?

Answer 29

amount of water/concentration of water
(highest bar psi = 0)

Question 30

dipol?

Answer 30

ends have diff charges
eg. H2O
= cohesion (ends stick together)/ adhesion (push away from each other)
happens cuz of H bonds

Question 31

What factors can influence the fluidity of the cell membrane

Answer 31

-Temperature
-Saturated vs unsaturated fatty acids
-Tail length (longer = more intermolecular forces = less fluid/permeable)
-Cholesterol

Question 32

Vesicles is animals vs plant

Answer 32

Membrane enclosed sac (often pinched off other organelles) used for transport and storage

Animals have many little vesicules
Plants have one large vacuole

Question 33

Endomembrane system

Answer 33

Rough endoplasmic reticulum: ribosomes produce polypeptides
Vesicules from smoot ER travel/bring polypeptides to Golgi apparatus where some are stored and some are processed further
Vesicules pinch off from the golgi appartus to the cell membrane or other destinations

Question 34

What do lysosomes and peroxisomes do?

Answer 34

Lysosomes: contain enzymes to catalyze hydrolysis (break down molecules)
*enzymes have a pH optimum of 5 so they are less likely to start breaking down the contents of the cytoplasm (pH 7.5)
Peroxisomes: catalyze retox reactions (break down fatty acids and hydrogo peroxide)

Question 35

What is the endoplasmic reticulum and what does it do?

Answer 35

System of channels and sacs composed of membranes enclosing a lumen: rough and smooth
- smooth: synthesizes lipids such as phosolipids
-rough: protein synthesis by the ribosomes then ER assembles them for transport