Exam 2 October

Question 1

Why do cell membranes contain more unsaturated fatty acids in cool climates?

Answer 1

The unsaturated fatty acid tails prevent packing and maintain fluidity as membrane cools

Question 2

How does cholesterol help maintain proper fluidity?

Answer 2

In cold temps, it prevents packing of phospholipids.

in warm temps, prevents drifting of phospholipids

Question 3

Permeability is _____ correlated with fluidity.

Answer 3

directly (p ^ then f ^) (p down then f down)

Question 4

Which molecules cross the membrane easily?

Answer 4

Non polar molec, O2, CO2, Steroids

Question 5

Which molecules cross slowly?

Answer 5

H2O, small polar molec, glucose

Question 6

Which molecules cross the membrane rarely?

Answer 6

Large polar or ionic molecules, ions, proteins, polysaccharides

Question 7

What are the important functions of proteins?

Answer 7

1. Enzymes > catalyze bio reactions
2. Contractile > muscles
3. Transport > both inside the cell, transport molec across cell membrane
4. Structural > cytoskeleton, maintaining cell shape

Question 8

What is a polypeptide?

Answer 8

Polymer

Question 9

What is an amino acid?

Answer 9

monomer

Question 10

What is secondary structure?

Answer 10

Formed when diff amino acids hydrogen bond to each other

Question 11

Can different sections of a polypeptide have different secondary structure or no ss?

Answer 11

YES

Question 12

what are the levels of structural complexity for a protein?

Answer 12

primary, secondary, tertiary, and quaternary

Question 13

What are the five forces that cause tertiary structure?

Answer 13

1. Hydrogen Bonds
2. Ionic Bonds
3. Disulfide Bridge
4. Hydrophobic Effect
5. Van der Waals forces

Question 14

What are Van der Waals forces?

Answer 14

they stabilize nonpolar amino acids on the inside of proteins

Question 15

What is quaternary structure?

Answer 15

2 or ore globular polypeptides bonded together to make a functioning protein, not all proteins have this level

Question 16

What is denaturing of a protein?

Answer 16

Damage/unfolding caused by heat and changes in pH

Question 17

What is sickle cell disease?

Answer 17

Change in the primary structure of hemoglobin, painful, causes blockages in arteries

Question 18

What is a prion?

Answer 18

nervous system protein with altered secondary structure

Question 19

What are some diseases that are caused by prions?

Answer 19

CWD, Mad Cow, Creuzfeldt-Jakob

Question 20

Why is carbon a good skeleton molecule?

Answer 20

• needs 4 bonds: allows for greater variety of 3D shapes

- almost always makes covalent bonds (strong)

Question 21

What are trans-fats?

Answer 21

partially hydrogenated fats, they rarely occur naturally, almost all are synthetically produced by hydrogenation

Question 22

What is bad about trans fats?

Answer 22

Solid at room temp, stick to arteries even better than saturated fats, as long as less than .5 g/serving no requirement to label

Question 23

What is a condensation reaction?

Answer 23

used to form all major biological molecules by bonding together momomers to make a larger polymer, always involves formation of H2O, aka dehydration reaction

Question 24

What is a dehydration reaction?

Answer 24

Condensation reaction- When bonding glycerol to a fatty acid, the bond formed is an ester bond or ester linkage

Question 25

What is a lipid?

Answer 25

fully or partially hydrophobic, mostly made of C and H, with some O aka fat

Question 26

What is saturated fat?

Answer 26

NO DOUBLE BONDS, triglyceride, 14-18 carbon long tails, solid at room temp, contribute to heart problems

Question 27

What is an unsaturated fat?

Answer 27

DOUBLE BONDS, triglyceride, most commonly produced by plants, considered to be more healthy, liquid at room temp

Question 28

Why are saturated fats solid?

Answer 28

Straight fatty acid chain means they are closely packed which = solid

Question 29

Why are unsaturated fats liquid?

Answer 29

They cant pack together due to kinks in tails.

Question 30

What is a steroid?

Answer 30

Many are hormones,consists of 4 carbon ring backbone, ex-> estrogen, testosterone, cholesterol

Question 31

What is a phospholipid?

Answer 31

The main molecule forming the structure of our cell membranes, ampipathic molecule

Question 32

What is an ampipathic molecule?

Answer 32

Has both hydrophillic and hydrophobic parts

Question 33

What is a micelle?

Answer 33

Fatty acid tails on a phospholipd <12 carbons long, and put in water, form a spherical micelle

Question 34

How does soap work?

Answer 34

Tails attach to oil and dirt where they get trapped inside the micelle, when rinsed, it removes micelle

Question 35

When does a phospholipid membrane form?

Answer 35

if fatty acid tails are >12 carbons long, and you put them in water, they form phospholipid bilayer

Question 36

What is the fluid mosaic model?

Answer 36

Individual molec in the cell membrane are able to flow past one another, membrane is fluid, w/a consistency of salad oil

Question 37

What is photosynthesis?

Answer 37

a process that converts solar energy to chemical energy in organic molecules, non spontaneous reaction

Question 38

What organisms are photosynthetic?

Answer 38

plants -> all bacteria -> some protists -> some

Question 39

What is the chemical equation for photosynthesis?

Answer 39

6CO2 + 6H2O + solar energy -> C6H12O6 + 6O2

Question 40

Why is photosynthesis important?

Answer 40

1. replaces biosphere energy lost to space | 2. produces diatomic oxygen

Question 41

How is light energy captured?

Answer 41

When light strikes a pigment, electrons in orbitals close to the nucleus move to orbitals farther away from the nucleus.

Question 42

What is a pigment?

Answer 42

Any molecule that can absorb light or sun energy | ex -> chlorophyll, carotenes, xanthophylls

Question 43

What is the visible range of light?

Answer 43

400 nm to 710 nm (purple to red)

Question 44

Why do plants appear green?

Answer 44

Plants reflect light in green range and thus appear green

Question 45

What light energy can pigments absorb?

Answer 45

light energy in the visible light range

Question 46

What happens when UV light strikes a pigment?

Answer 46

It creates free radicals (jumping electrons)

Question 47

What does UV light do?

Answer 47

nothing, it cant move electrons to higher orbitals

Question 48

What is the purpose of photosystems II and I ?

Answer 48

to capture energy and send energy & electrons to the calvin cycle

Question 49

What is the purpose of the calvin cycle?

Answer 49

To use energy and electrons and CO2 to make glucose

Question 50

What are the products of photosystems II and I?

Answer 50

ATP and NADPH

Question 51

What is ATP?

Answer 51

intermediary molecule with purpose of energy storage

Question 52

What is NADPH?

Answer 52

An electron carrier

Question 53

What is the stroma?

Answer 53

Watery fluid inside chloroplast, site of the calvin cycle

Question 54

What is the thylakoid?

Answer 54

"stacked disc" in the chloroplast, embedded proteins in its plasma membrane are site of photosystem II and I

Question 55

What is the thylakoid lumen?

Answer 55

Fluid filled cavity in thylakoid

Question 56

What is diffusion?

Answer 56

Net flow of molecules from areas of high concentration to low concentration, due to natural random motion of molecules

Question 57

When two sides of membrane have reached equilibrium...

Answer 57

...the flow is equal in both directions

Question 58

What is osmosis?

Answer 58

Name for diffusion of H2O through a semi-permeable membrane results in net flow of water from areas of high concentration of free water to areas of lower concentration of free water

Question 59

What is crenation?

Answer 59

Shirvelling of animal cells when water flows out of cell

Question 60

Hypertonic

Answer 60

Higher concentration of solute

Question 61

Hypotonic

Answer 61

Low concentration of solute

Question 62

What are the 4 major biological molecules?

Answer 62

Proteins, carbohydrates, lipids, nucleic acids

Question 63

What are the 3 forms of a carbohydrate?

Answer 63

1. Monomer -> monosaccharide | 2. Polymer -> disaccharide or polysaccharide

Question 64

What is the function of a carbohydrate?

Answer 64

Carbohydrates are energy molecules used by cells during cell respiration and fermentation

Question 65

Alpha 1-4 glycosidic linkage

Answer 65

Very easy for enzymes to disassemble (hydrolyze), function is energy storage, starch and glycogen are examples of polysaccharides with this bond

Question 66

Beta 1-4 glycosidic linkage

Answer 66

Very difficult for enzymes to break apart, structural, seen in polysaccharides chitin and cellulose