exam 1: lecture 1 Flashcards

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1
Q

what 3 branches of study in cell biology a combination of?

A

Cytology
Biochemistry
Genetics

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2
Q

what is cytology

A

the study of cells
the beginning of cell biology

-an observation where it is just looking- not experiment or interaction.

not until biochemistry and genetics that there were interactions or experiments

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3
Q

what is cell biology?

A

a cell-level zoology
what does a zoologist do? study how the animal functions
-> cell biology is the same: how they move, make energy, reproduction, organelles, and different types of cells

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4
Q

micrometer

A

1/1,000,000th meter (million)
ex. bacteria (prokaryotes), nucleus, mitochondria

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5
Q

nanometer

A

1/1,000,000,000th meter (billion)
ex. mycoplasma, viruses, ribosomes,proteins, lipids, small molecules, atoms

uses electron microscope

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6
Q

number of electron in each shell orbital

A

1st: 2
2nd: 8
3rd:8

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7
Q

what is valence number

A

the number of electrons that are needed to fill the orbitals

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8
Q

what are covalent bonds

A

bonds that are made by sharing of electrons of molecules ( missing valence electrons)

-strong: takes energy to break (heat from fire, electricity)

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9
Q

the importance of carbon: organic chemistry

A

the study of all classes of carbon-containing compounds

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10
Q

the importance of carbon: biochemistry

A

the study of chemistry of living systems

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11
Q

what is the most important atom in biological molecules?

A

carbon

specific bonding properties of carbon account for the characteristics of carbon-containing compounds

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12
Q

bonding properties of carbon

A

carbon has 4 valance electrons, which means it can form 4 bonds

most likely to form covalent bonds with C,H,O,N,S

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13
Q

what is a covalent bond

A

the sharing of a pair of electrons

stable

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14
Q

why are strong covalent bonds necessary for life

A

high energy such as UV light is more hazardous to the molecules (nucleic acids are sensitive)
->the visible light is lower in energy than C bonds
=>visible light cannot break of he bond of covalent bonds

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15
Q

what are ionic bonds

A

weaker than covalent bonds
ions: imbalance between protons and electrons (have a charge)

cation: loss of electron (+) ~ Na+
anion: gain of electron (-) ~ Cl-

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16
Q

structure of sodium chloride

A

a crystal
how to break ionic bonds? water (the molecules will dissociate)

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17
Q

what are hydrogen bondings

A

The bonding of H with other charged atoms

ex.h2o
H has a smaller nucleus-spends more time around the oxygen
->uneven electrons sharing=> polar charged

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18
Q

what makes water molecules polar?

A
  1. unequal distribution of electrons
  2. geometry: bent, not linear
  3. the O atom has a slight negative charge that draws H atoms around it
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19
Q

what bonds water molecules tgt?

A

hydrogen bond
=1/10 as strong as covalent bonds

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20
Q

How are water molecules cohesive?

A

due to their polarity, they are attracted to each other as the electronegativity of oxygen draws other electropostive H nearby

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21
Q

what are the effects hydrogen bonds have on water

A
  1. surface tension
  2. boiling point
  3. specific heat
  4. heat of vaporization
  5. freezing point: salt content plays a role in water not freezing
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22
Q

what are the two weak molecular interactions

A
  1. van der waals
  2. hydrophobic interaction
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23
Q

what are van der waals interactions

A

the weak attraction between two atoms ONLY IF THE ATOMS ARE VERY CLOSE TGT AND ORIENTED CORRECTLY

-atoms that are too close will repel
-van der Waals radius: defines how close other atoms can come to it= the basis for space-filling models
=explains why molecules are certainly distanced

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24
Q

what are hydrophobic interactions

A

the behavior of nonpolar groups- will try to minimize contact with water
-> cause nonpolar groups to be found in the inside of a protein or a membrane

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25
Q

Building block of the cells

A
  1. sugars (carbohydrates)-> polysaccharides
    2.fatty acids (lipids)-> fats, membranes
  2. amino acids-> proteins
  3. nucleotides (DNA/RNA)-> nucleic acids

+WATER

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26
Q

why is water so important biochemically?

A
  1. Most nutrients are dissolved in water
  2. water heps the transport of food and wastes in/out of cells
  3. water is the medium for most reactions
  4. water makes up on avg. to 65-75% of a cell’s mass
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27
Q

How do hydrogen bonds make water a special molecule

A
  1. being able to form hydrogen bonds, this allows it to have a high boiling point and a low freezing point
    ->water freezes from the top down unlike other nonpolar molecules
  2. its polarity makes it an excellent solvent
  3. can act as a donor of hydroxide (OH-) and hydrogen (H+)
    H2O–dissociates–> H+ & OH_
  4. makes water an excellent temp. buffer
    -small scaled: slow exchange of heat
    -large scale: during the summer, water will stay cold for a while due to the cold climate of winter has heat is lost during the summer
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28
Q

How does water have high temp-stabilizing capacity

A

high specific heat
-> water changes temp slowly, protecting living systems from extreme temp changes
= without this, the energy released into cells would lead to overheating and death

29
Q

water freezes from the topdown, but wy does ice float?

A

in ice, water molecules from a crystal lattice, which is less dense

in liquid water, no lattice forms, so liquid water is denser than ice

30
Q

what is diffusion

A

the movement of molecules that goes to an area of high concentration to an area of low concentration

31
Q

what is osmosis

A

the diffusion of water

principle 1: concentration is the amount of a particular molecules per set volume (200gm/L)

principle 2: more solute-> diluted water
-more stuff dissolved in water, the lower the concentration of water

32
Q

hypotonic

A

“pop”
more solute inside-> water moving in

33
Q

hypertonic

A

shrink
less solute inside->water moving out

34
Q

Examples of homeostasis

A

water balance
regulations of ions
regulations of sugar levels

35
Q

pH scale

A

7: OH-=H+
7-14: OH->H+ (base:10^14)
0-7: OH-<H+ (acid: 10^1)

36
Q

Functions of Sugars (CHO)

A

1) nutrient for energy
2) nutrient storage
3) structural function in cell walls
4) signal transduction (recognition, transportation)

37
Q

How many carbons monosaccharides have

A

3 or more carbons
(H have double the # of C & O)

38
Q

the difference between glucose and fructose

A

same chemical formula
the difference is where the double bond is

39
Q

how are macromolecules synthesized

A
  1. synthesized by the stepwise polymerization of monomers
  2. condensation (monomers are put tgt by losing water)
  3. activated monomers must be present- coupled with a carrier molecule
  4. energy for coupling is provided by ATP
  5. directionality-differs at each end
40
Q

what is condensation

A

monomer in, water out

41
Q

what is hydrolysis

A

water in, monomer out

42
Q

what is a glycosidic bond

A

a covalent sugar bond that connects sugars

43
Q

Beta glycosidic bond

A

galactose-glucose
cellulose
STRAIGHT-180 turns to each other
-> easy hydrogen bonding between monomers and its neighbors= stable structure & resistant to hydrolysis

44
Q

alpha glycosidic bond

A

starch/glycogen
BEN-longer and father apart–> circular structure

45
Q

glucose and fructose form what sugar

A

sucrose

46
Q

What are storage polysaccharides?

A

starch in plant cells
glycogen in animal cells & bacteria
* consists of alpha units linked by alpha glycosidic bonds (1-4) [1-6: side chains)

47
Q

storage polysaccharides: glycogen

A

in animals and bacteria
highly branched, the branches 8-10 unis
mainly in the liver (glucose) & muscle tissue (muscle contraction)

bacteria store glycogen as a glucose reserve

48
Q

storage polysaccharides: starch

A

*glucose reserve in plants
*unbranched amylose (10-30%)
*branched amylopectin (70-90)- alpha 1-6 branches once every 12-25 units (longer than glycogen)
*starch grains in plastids
amyloplasts: starch storage

49
Q

structural: cellulose

A

repeating monomers of beta units (1-4)
*chitin: cell walls of fungal cells and insects exoskeletons

50
Q

functions of proteins (CHONS)

A

1) structrual- cytoskeleton
2) enzymatic activity
3) signal transduction functions
4) nutrient

51
Q

what are 2 types of chemical in the cells

A

anabolic: to build
A+B-> AB

catabolic: to break down
AB-> A+B

52
Q

enzymes

A

speed up chemical reactions @ low temp.
lowering activation energy

53
Q

Lock and key model

A

have specificity between substrate and enzyme

proximity is important because if they’re close tgt, then they use less energy to “bang” them tgt

54
Q

how are amino acids held together

A

by peptide bond with condensation (dehydration)
amino group (N terminus) to carboxyl group (C terminus)

peptide bond-stable and stiff

55
Q

levels of protein structure

A

primary
secondary: motifs (substructure)
tertiary structure: final 3D structure (active site + substrate)
quaternary : multiple monomers join tgt

56
Q

protein structure: primary

A

formal designation sequence
written from N-terminus to C-terminus
insulin: 1st to have its sequence known
–> 1 alpha + 1 beta subunit with 21 & 30 amino acids

57
Q

“intra” vs “inter”

A

intra: w/in chain
inter: between 2 peptide chains
form by a disulfide bond (condensation/ dehydration)

58
Q

what is the importance of primary structure?

A

genetically: specified by the order of nucleotides in mRNA

structurally: order + identity directs the formation of higher-order structures

59
Q

protein structure: secondary

A

describes local regions that result from hydrogen bonding betwen NH and CO groups with the backbone
= result in alpha helix & beta sheet

60
Q

secondary structure: alpha helix

A

spiral: peptide backbone with r group jutting out
3.6 aa per turn

hydrogen bond: NH group of one aa & the CO group of a second aa that is one turn away from the first

61
Q

secondary structure: beta sheet

A

sheetlike conformation with “peaks” and “troughs”
r groups are on alternating sides

same polarity: parallel
opposite polarity: antiparallel

62
Q

protein structure: tertiary structure

A

*depends on the interactions of the R-groups
not repetitive
*neither repetitive/easy to predict
—> the sum of hydrophobic residues avoiding water, hydrophilic residues interacting water, the repulsion of same charged residues, and attraction between oppositely charged residues

63
Q

Tertiary structure: native conformation

A

most stable 3D structure

64
Q

what are the two board categories?

A

1) fibrous
2)globular

65
Q

Fibrous proteins

A

highly ordered, repetitive structure
ex.
fibroin of silk
keratin of hair and wool
collagen in tendons and skin
elastin in ligaments and blood vessels

66
Q

globular proteins

A

folded in compacted structures
unique structure:
-alpha helical (ball & stick model)
-beta sheet (spiral & ribbon model)
-a mixture of both

67
Q

What are the interactions that determine the tertiary structure of proteins?

A

1) hydrogen bond:
-between peptide groups
-side chains &peptide bonds
-between 2 side chains

2) hydrophobic interaction
-push h2o have hydrophobic chains near each other

3) ionic bond
4) disulfide bond

68
Q

protein structure: quaternary structure

A

subunit interactions & assembly
–> multimeric proteins: multiple identical subunits
ex. hemoglobin

formation is spontaneous with the help of chaperone molecules