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IB BIOLOGY 2017 EXAM > Molecular Biology > Flashcards

Molecular Biology Flashcards

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1
Q

Catabolism

A

breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers

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2
Q

Anabolism

A

synthesis of complex molecules from simpler molecules, including the formation of macromolecules from monomers using condensation reactions

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3
Q

Metabolism

A

web of all enzyme-catalyzed reactions in a cell or organism

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4
Q

four biochemical groups

A
  • carbohydrates
  • lipids
  • proteins
  • nucleic acids
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5
Q

Why is life based on carbon

A
  • it can form four covalent bonds; creates stable molecules
  • allows for a diversity of molecules (bonds easily)
    Not very reactive
    Very small
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6
Q

elements in living organisms

A
  • hydrogen
  • oxygen
  • nitrogen
  • phosphorous
  • carbon
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7
Q

monomers/dimers/polymers of carbohydrates

A

monomer; monosaccharides
dimers; disaccharaides
polymers; polsaccharides

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8
Q

monomers/dimers/polymers of lipids

A

monomers; glycerol, fatty acids, phosphate groups

dimers/polymers; triglycerides, phopholipids, steroids (FAT)

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9
Q

monomers/dimers/polymers of proteins

A

monomer; amino acids

dimer/polymer; polypeptides

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10
Q

monomers/dimers/polymers of nucleic acids

A

monomer; nucleotide

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11
Q

What determines if a reaction occurs or not?

A
  • identity of colliding molecules
  • orintantation of colliding molecules
  • speed/kinetic energy of molecules
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12
Q

why do cells use enzymes

A

to icnrease the likelihood that a succesfull collision wil lead to a useful reaction

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13
Q

what are enzymes

A

protein molecules with a specific shape that a react can fit into at the active site

  • act as catlyusts
  • increase rate of reaction
  • lower activation energy
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14
Q

what explains the properties of water?

A
  • dipolarity

- hydrogen vonding

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15
Q

what makes water so special

A

its polar and hydrogen bonds form between them

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16
Q

why is water polar

A

due to the unequal sharing of electrons within the water molecule that makes oxygen slightly negative and hydrogen slightly positiveq

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17
Q

cohesive properties of water

A

Cohesion: attraction of water molecules to other water molecules
- due to hydrogen bonds that form between water molecules due to polarity

explains;

  • why water forms into droplets when it is spilt
  • why water has a surface tension that allows for some animals to walk/run on it
  • why water can move as a water column in the xylem
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18
Q

thermal properties of water

A
  • high latent heat of vapourization
  • high specific heat capacity

explains;

  • water can absorb a great deal of heat (good for chemical reactions)
  • act as a coolant
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19
Q

solvent properties of water

A

excellent solvent;
water molecules are polar and therefore can dissolve other polar molecules (e.g. ‘like dissolves like’)

  • disolves glucose, amino acids, fibringoen and hydrogen carbonate ions in BLOOD
  • if there is a non-polar substance, plasma membranes, blood proteins, vesicle or transport proteins are used to transport it
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20
Q

specific heat capacity

A

large amount of heat causes a small increase in temperature (energy required to raise the temperature of 1 g of a substance)

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21
Q

latent heat of vaporization

A

a large amount of heat energy is needed to vaporize/evaporate water

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22
Q

adhesive properties of water

A

Adhesion: is the formation of hydrogen bonds between the water molecules and F, N and O (attraction between unlike molecules)

explains;
why water sticks to the vascular tissue in plants (fight gravity!) and can be pulled up

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23
Q

bonds formed during condensation reactions

A

BONDS:

  • ester bond (triglycerides)
  • glycosidic bond (maltose)
  • peptide bond (amino acids)
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24
Q

hydrophyllic

A
  • water loving

- polar substance

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25
Q

hydrophobic

A
  • water hating

- non polar substance

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26
Q

General formula of carbhydrates

A

General formula: (CH2O)#

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27
Q

function of carbohydrates

A

primary source of energy (e.g glycogen is a short term energy source for the body)

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28
Q

Monosaccharides

A

glucose
fructose
galactose
ribose

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29
Q

Disaccharides

A

sucrose
maltose
lactose

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30
Q

Polysaccharides

A

starch
cellulose
glycogen

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31
Q

cellulose

A
  • major component of cell walls
  • helps give rigidity.support to plant parts such as roots, stems and leaves

Structural polysaccharide in plants
B-glucose
1:4 glycosidic bond
Unlike starch, cellulose is very strong and prevents cells from bursting when they take excess water
Consists of long chains of glucose molecules

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32
Q

starch

A
  • organic products of photosynthsis are stored in plants as starch
  • typically as starch granules in chloroplasts or in plant storage areas such as roots or root structures
  • two sub-componenents; amylopectin and amylose
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33
Q

glycogen

A
  • animals stores excess glucose in this form

- stored in liver and muscle areas

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34
Q

Lipids function

A
  • long term storage of energy
  • they are important components of the cell membrane
  • they are used as a heat insulator
  • can act as a shock absorber
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35
Q

3 MAIN TYPES:Lipid

A
  1. triglycerides (Fats + Oils)
  2. Phospholipids (components of cell membrane)
  3. Steroids (Cholesterol, progesterone, estrogen, testosterone)
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36
Q

what are TRIGLYCERIDES composed of

A

TRIGLYCERIDES;
tri: refers to 3 fatty acids chains

  • glycerol
  • fatty acids
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37
Q

SATURATED FATTY ACID:

A

if the bonds between carbon atoms are SINGLE
the fatty acids contain as much hydrogen as they possibly could

animal sources (red meats, milk, etc.)&raquo_space;> FATS

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38
Q

UNSATURATED FATTY ACID

A

UNSATURATED FATTY ACIDS
when the fatty acids contain 1 or more DOUBLE BONDS
contains less hydrogen atoms than it could (unfulfilled)

Plants (Oil)

can be polyunsatured or monoundsatured

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39
Q

CIS and TRANS unsaturated Fatty acids

A

CIS:(can be poly)
same side C=C bond
when hydrogen atoms are on the same side with respect to the double bond
TRANS:(can be poly)
-when the hydrogen atoms are on the opposite side with respect to the double bond

CIS= Healthy
Trans= unhealthy

cis-fatty acids cannot line next to each other, thats why the are lipid at room temperature
cis fatty acids are ‘slippery’ and will not clog arteries
Trans Fatty Acids
-hydrogenation of vegetable or fish oils
-modification of natural, healthy oils
-hydrogenation changes the shape of the oil
-trans fats are illegal
-turns it from liquid» solid

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40
Q

PHOSPHOLIPIDS

A

these are modified triglycerides that have one fatty acid chain by a phosphate group

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41
Q

Scientific Evidence of trans unsatured fats health risk

A

Coronary heart disease: arteries become blocked due to fatty deposits

High intake of transfat
CHD: found in patients who take more cis unsaturated fatty acids

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42
Q

BMI

A

BMI: body mass index, reflects heigh and weight

  1. 5> underweight
  2. 5-24.9 Normal weight
  3. 0-29.9 Overweight
  4. 0< Obese
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43
Q

BMI formula

A

FORMULA: weight (kg)/[height (m)x height (m)]

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44
Q

energy storage in humans

A
  • storing glucose as glycogen in liver and muscle cells

- storing triglyceride lipids within adipose (fat) cells

45
Q

FUNCTIONS OF PROTEINS:

A

FUNCTIONS OF PROTEINS:

structural, catalytic, signalling, immunological

46
Q

how man naturally occuring amino acids are there

A

20 (humans produce 10; rest have to be injested)

47
Q

what is the AA sequence coded for

A

genes

48
Q

rubisco

A

short hand name for enzyme that catalyzes the first reaction of carbon fixing reactions of photosynthesis

49
Q

insulin

A

a protein hormone produced by the pancreas that results in a decrease of blood sugar levels and an increase of sugar inside body cells

50
Q

immunoglobin

A

an antibody that recognizes an antigen as part of the immune response

51
Q

rhodopsin

A

pigment found in eye retina for low light conditions

52
Q

collagen

A

main protein component of connective tissuem which is in skin, tendons and ligaments

53
Q

spider silk

A

fibrous protein spun by spiders for webs, lines, nest bulding, hunting

54
Q

how do the proteins differ from each other?

A

Length: different # of amino acids
Types: different types
Order: different order

55
Q

primary structure of protein

A
  • linear sequence of AAs
  • contains only peptide bonds
  • in nature: proteins are almost never found in this structure because they fold to produce more complex molecules
56
Q

secondary structure of protein

A
  • the polypeptide chain folds to form: alpha helix or beta pleated sheet
    examples: keratin (alpha helix) and silk (beta pleated sheet)
  • these structures are held together by hydrogen bonds
57
Q

tertiary structure of protein

A
  • alpha helix and beta pleated sheets fold into compact globules
  • the structures are held together by: hydrogen bonds, ionic bonds and disulphide bonds
  • example: enzymes
58
Q

quaternary structure of protein

A
  • examples: hemoglobin, collagen, insulin

- held together by: hydrogen bonds, ionic bonds, disulphide bonds

59
Q

Fibrous Protein

A

Shape: Long and narrow

Role: Structural (strength and support)

Solubility: Generally insoluble in water

Sequence: Repetitive amino acid sequence

Stability: Less sensitive to change in heart and pH

Examples
Collagen, myosin, fibrin, actin, keratin, elastin

60
Q

Globular Protein

A

Shape: Rounded/spherical

Role:Functional (catalytic, transport, etc)

Solubillity: Generally soluble in water

Sequence: Irregular amino acid sequence

Stability;More sensitive to change in heat, pH, etc

Examples:
Catalase, haemoglobin, lipase, insulin, immunoglobulin, DNA Polymerase, Oestrogen

61
Q

PROTEOME:

A

PROTEOME: all of the proteins produced by a cell, tissue or organ in a human
- as cells can differentiate they dont have to produce the same proteins to have the same genome

62
Q

Protein Denatureation

A
  • proteins can denature by heat and pH environment alteration (bonds broken and proteins get broken down into simpler forms/become inactive)
  • each protein has an optimum temperature
63
Q

ENZYMES

A

ENZYMES “special proteins”
Functions:- speed up reactions, they act as a catalyst
Long chain of amino acids (globular protein in tertiary structure)
Substrate»>enzyme»>product

64
Q

Active site

A

a small region on the enzyme where the substrate binds to and the reaction takes place, enzymes are substrate specific

65
Q

Catalyst:

A

increase rate of reaction without themselves reaction without being being used up.

66
Q

STEPS OF AN ENZYMATIC REACTION

A
  1. substrate enters active site
  2. enzyme-substrate complex is formed
  3. substrate is changed into a different chemical (product)
    at the end of the reaction, the product leaves the active site

AT THE END:
-enzymes are never permanently modified, they can return into their original state, to be used over + over again

67
Q

two enzymatic reaction theories

A

Lock and key

Induced Fit

68
Q

Lock and Key Hypothesis

A

Lock and Key Hypothesis
the substrate molecular shape is the exact match to the enzyme’s active site
the substrate fits perfectly into the enzyme’s active site, the way a key fits into a lock. Each substrate has a particular corresponding enzyme

69
Q

Induced-Fit Hypothesis

A

-the substrate binds to the enzyme’s active site
the enzyme changes shape to fit and hold the substrate
now the enzyme active site fits,
Forces substrate into distorted active site= makes or breaks substrate by force
the strain to fit breaks/makes bonds

70
Q

Factors affecting enzyme activity

A

Temperature
-as temperature increases so does enzyme activity
this is because:
molecules move faster (most often substrate moves around, but enzyme can as well) causing more of a chance for the enzyme and the substrate to find each other and bind
Optimum temperature
when the activity of an enzyme is at its greatest (any point beyond that the activity declines because they begin to break)

SUBSTRATE CONCENTRATION

Denaturation
change in the shape of an enzyme, for example:
-an active enzyme is tridimensional
-when it is heated it loses shape because heat causes the enzyme to twist and bend, and the hydrogen bonds to break
-this affects its activity to recognize the substrate (because of the change in the shape of the active site

71
Q

Stages of Denaturation

A
  • Quaternary Structure lost = protein subunits are dissociated
  • Tertiary structure lost = interaction between side chains of amino acids are lost (hydrogen bonds/ionic bonds)
  • Binary Structure lost = proteins lose patterns such as alpha helix and beta pleated sheet and become random coil configurations
  • Primary structure = the sequence of amino acids (peptide bonds) remains
72
Q

Change in pH

A

each enzyme has an optimum pH
-change in pH could result in change in the shape of the enzyme (new shape may not be active)
optimum pH of pepsin is 2
optimum pH of lipase is 8

73
Q 
Optimum pH of/location:
pepsin
amylase
lipase
lactase
A

Pepsin.» PH2 (Stomach
Amylase» PH7 (mouth, small intestine, pancreas)
Lipase» PH8 (small intestine)
Lactase&raquo_space; PH7 (small intestine)

74
Q

Use of immobilized enzymes

A
  • used as catalysts in industry
  • enzymes can be held in tiny pores on beads called calcium alginate (trapped there; immoblixed) so enzymes can be recovered and reused in processes

-used in the production of lactose-free milk for lactose intolerant people (enzyme lactase is immoblized to break dont lactose into glucose and galatcose and digest it)

75
Q

Nucleotide

A

a molecule containing a phosphate group attached to a pentose sugar and base

76
Q

DNA

A

deoxyribose nucleic acid, code for life and all the functions in a living organism

  • a double stranded helix
  • sugar phosphate backbone
  • anti parallel
  • nitrogen containing
  • hydrogen bonding and phosphdiester bonds
  • found in nucleos
  • pentose sugar- deoxyribose
77
Q

Crick and Watson and Rosalind Franklin:

A

discovered the structure of DNA

78
Q

nucleotide bases

A

PURINE:

  • adenine
  • guanine

PYRAMIDINE:

  • thymine
  • cytosine
  • uracil (only in RNA)
79
Q

RNA

A

Single stranded

Ribose sugar

Uracil (GCUA)

Nucleic Acid

Found in nucleus and outside of it (can travel out)

Has pentose sugar

Three types: tRNA, mRNA, rRNA

80
Q

Matthew Meselson and Franklin Stahl

A

Geneticists and molecular biologists that worked together to discover the semi-conservative replication of DNA

81
Q

what did Matthew Meselson and Franklin Stahl do

A

They found a way to mark the parent DNA molecule using an isotope of nitrogen with an extra neutron (N14 and N15), allowing them to show 1 old strand and a newly synthesized strand
They used E.Coli bacteria in the experiment

82
Q

SEMI CONSERVATIVE REPLICATION:

A

Theory: mechanism of DNA replication where two new copies of DNA are produced from an original DNA strand consisting of one of the original strands and one new strand

83
Q

What did Meselson and Stahl do?

A

mRNA
rRNA
tRNA

84
Q

OTHER REPLICATION THEORIES:

A

Conservative: parental DNA is conserved

Dispersive (fragmented) : mixture of old and new DNA within the same chromosome

85
Q

mRNA

A

messenger RNA. Copy of a gene, carries information to make a protein

86
Q

rRNA

A

ribosomal RNA, component of ribosomes. Large and small subunit

87
Q

tRNA

A

transfer RNA. Brings amino acids to ribosomes during protein synthesis, has a site for the AA to attach and an anticodon (determines which of the 20 AA’s is attached to the tRNA)

88
Q

enzymes in replication

A

DNA Helicase: separates the two DNA strands before replication
DNA Polymerase I: catalyzes the formation of new polynucleotide chain
DNA ligase: joins together short sections of the lagging strand

Single-stranded binding protein: keeps the separated DNA strands apart during replication

89
Q

DNA Helicase

A

DNA Helicase: separates the two DNA strands before replication

90
Q

DNA Polyermase I

DNA Polymerase II

A

DNA Polymerase I:
Removes the primer and replaces it with DNA

DNA POLYERMASE III;Synthesized new strand by adding nucleotides onto the primer in a 5’ to 3’ direction

91
Q

DNA Ligase

A

DNA ligase: joins together short sections of the lagging strand (okazaki fragments)

92
Q

Single-stranded binding protein:

A

Single-stranded binding protein: keeps the separated DNA strands apart during replication

93
Q

Polymerase Chain Reaction

A

developed in 1970’s

  • artificial DNA replication
  • duplicates short segments of DNA
  • scientists can produce large quantities of DNA this way for study
  • used for forensics studies and paterntity testing
  • Process consists of fluctuating temperatures
94
Q

Cell respiration:

A 
Cell respiration: controlled release of energy from organic compounds to produce ATP
Its how the body gains energy
Chemical reaction within all cells
TYPES:
Aerobic
Anaerobic
95
Q

AEROBIC:

A

AEROBIC:
Normal form of respiration through breathing (muscular contraction)
Glucose + oxygen —–> carbon dioxide + water + energy (ATP)
C6H12O6 + 6O2——> 6CO2 + 6H2O + 36ATP

96
Q

ANAEROBIC: respiration

A

ANAEROBIC:
When the body is getting no oxygen from breathing, so the cell creates energy just with glucose (inefficient)
In humans: glucose —–> Lactic Acid + Energy
C6H12O6—–> 2C3H6O3 + 2 ATP

97
Q

anaerboic respiration

A

Anaerobic respiration is the act gaining ATP without oxygen from the pyruvate
- only 1-2 ATP produced

98
Q

alcoholic fermentation

A
  • yeast
  • produces ethanol, carbon dioxide
  • use of fermentation in baking and alochol production
99
Q

lactic acid fermentation

A

-organisms can respire without oxygen
-produce lactic acid by breaking down pyruvate
-e.g. during excersize
Lactic acid causes muscular fatigue and pain, forms crystals in the muscle tissue that makes the movement hard, toxic to body

OXYGEN DEBT: oxygen needed to break down lactic acid into carbon dioxide and water

100
Q

Why are leaves green?

A

Chlorophyll in chloroplasts

101
Q

PHOTOSYNTHESIS

A

CO2 + H2O ——–> O2 + C6H12O6
Photosynthesis is the production of carbon compounds in cells using light energy

Oxygen is produced from the photolysis of water (splitting of light)

102
Q

what wavelengths does visible light have

A

between 400-700 nm

103
Q

Electromagnetic spectrum

A

light energy is needed to produce carbon compounds from carbon dioxide
Visible spectrum: green is in the middle
- violet is the shortest and red the longest wavelength
-IR and UV

104
Q

what do substances do when hit with a particular wavelength of light

A
  • absorb it

- reflect it

105
Q

what does chlorphyll do when hit by light (and why are plants green?)

A
  • its a green pigment; reflects green light and absorbs all other wavelengths of the visible light spectrum (red and blue are absobved and used for photosynthesis)
106
Q

PHOTOSYNTHETIC PIGMENT:

A

PHOTOSYNTHETIC PIGMENT: colored biological compound that is present in chloroplasts and photosynthetic bacteria, and which captures light energy for photosynthesis

107
Q

LIMITING FACTORS OF PHOTOSYNTHESIS:

A

LIMITING FACTORS:
1. Temperature: has an optimum temperature, when it gets an higher, the rate goes down, as the plants begin to deteriorate

  1. Carbon Dioxide: reaches a max concentration, after there is no change in the rate
  2. Light Intensity: reaches a max intensity, after there is no change in the rate
108
Q

steps of photosynthesis

A
  1. light dependent; photolysis

2. light indepdent; production of carbon compounds

109
Q

measuring rate of photosynthesis?

A
  • by oxygen consumed
  • by carbon dioxide produced
  • by water used

IB BIOLOGY 2017 EXAM (11 decks)

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