Unit 2 - Cellular Chemistry/Macromolecules Flashcards
(58 cards)
1
Q
Lipid Bilayer
A
-double layered sheet of lipids which is studded with proteins
lipids
-serve as permeability barrier
-carbohydrates are attached as well
-all lipids in membrane are amphipathic
-composition varies
-form spontaneously
closed, self-sealing, important feature for cell fusion
-energetically favourable state is sealed compartment
2
Q
Lipid aggregates in water
A
-form surface film and small micelles
3
Q
Phospholipids
A
- major component of cell membranes
- polar head group and 2 hydrophobic fatty acid tails
- two -OH groups in glycerol are linked to fatty acids, while 3rd -OH group is linked to phosphate group
- phosphate is further linked to an alcohol
- amphipathic
4
Q
Unsaturated Fats
A
-one or more double bonds in hydrocarbon tail
-double bond creates kink in chain, allowing for 2 transfigurations:
1. cis - same side
2. trans - opposite side
liquid at room temp.
5
Q
Saturated Fats
A
-no double bonds in hydrocarbon tail
-linear molecule
solid at room temp.
6
Q
Steroids
A
-common multiple ring structure
7
Q
Fats/Oils/Triglycerides
A
-glycerol with 3 fatty acids attached to it
long hydrocarbon chain (tail) - not very reactive
-carboxyl group (head) - behaves as an acid, chemically reactive
-stored as energy reserve through ester linkage to glycerol to form triacyglycerols
8
Q
Functions of Carbs
A
- structural
- cell-to-cell recognition
- energy storage (short term)
9
Q
Glycosidic Bonds
A
- bond formed between -OH group on one sugar and -OH group on another through a condensation reaction - water is expelled as the bond is formed
- bond created through condensation reaction can be broken though hydrolysis in which a water molecule is consumed
10
Q
Cellulose
A
- polymer of beta-glucose
- joined by b-1,4 linkages
- hydrogen bonding between adjacent strands
- extremely stable, most abundant organic molecule on earth
11
Q
Glycogen
A
- storage form of energy in plants
- consists of highly branched a-1,4 and a-1,6 bonds
12
Q
Geometry of bond depends on… (carbs)
A
- whether OH group on C1 is in alpha or beta position
2. which C of the other sugar is involved in the linkage
13
Q
Formation of Disaccharides
A
- monomers linked when C1 of one binds to C of another (usually C4)
- carbon of first molecule determines structure of bond
14
Q
Anomers of Glucose
A
- alpha-glucose = below plane of molecule
- beta-glucose = above plane of molecule
15
Q
Structural features of sugar monomers include…
A
- carbonyl group
- lots of -OH groups
- monosaccharides form rings in solution
- isomeric forms have identical chemical groups but are arranged differently: structural isomers (bonded to different carbons) or stereoisomers (bonded in different orientation
16
Q
Glycolipids
A
-carbohydrates attached to lipids
17
Q
Glycoproteins
A
-carbohydrates attached to proteins through covalent bonds
18
Q
Polysaccharides
A
very long sugar chains
19
Q
Monosaccharides
A
simple sugars
20
Q
Secondary Structure of RNA
A
- hydrogen bonds form between complementary base pairs
- final molecule is single-stranded
- complex folds result in some RNA having catalytic activity
21
Q
Higher Order DNA Structure
A
- allows for short packaging and strict regulation of gene expression
- each DNA molecule is packaged into mitotic chromosome
22
Q
DNA Double Helix
A
- stabilized by hydrogen bonds & hydrophobic interactions
- entire molecule is water-soluble
23
Q
Secondary Structure of DNA
A
- two strands of DNA align anti-parallel with bases facing inwards hydrogen bonds between bases
- A pairs with T and C pairs with G
24
Q
Polymerization
A
- endergonic condensation reaction
- involves making of new phosphodiester bonds forming 2 nucleotides
- occurs because energy level of free nucleotides is first raised by addition of two phosphate groups
- NTP generates NMP present in monomer
25
Phosphodiester Linkage
- between 5' and 3' carbon atoms
| - joins nucleotides together
26
Functions of Nucleotides
1. monomeric units of RNA and DNA
2. important signal molecules within cells
3. important agents in energy transfer reactions of metabolism
4. act as coenzymes/cofactors
27
nucleoside
does not have phosphate group
28
nucleotide
- consists of a nitrogenous base
- a pentose sugar
- a phosphate group (makes nucleotide negatively charged)
29
To build RNA we require...
1. Phosphate group
2. ribose sugar
3. Base (A, U, C, G)
30
To build DNA we require...
1. Phosphate group
2. Deoxyribose sugar
3. Base (A, T, C, G)
31
RNA
- ribonucleic acid
| - directs ordering of amino acids into peptide chain
32
DNA
- deoxyribonucleic acid
| - sequence of subunits in DNA polymer directs RNA synthesis
33
Functions of proteins`
1. Enzymes --> catalyzing reactions
2. Transport
3. Support
4. Signalling
5. Movement
6. Defense
34
Misfolding
-many human diseases caused by this
-protein can fold properly at first, but then it may unfold ---under certain conditions
when the protein misfolds, it disrupts the cell's activity, leading to its premature death
35
Renaturation
-when a protein is able to fold back up
36
Denaturation
-when a protein is unfolded back to its primary structure
37
4th structure of proteins
- when two or more polypeptides interact to form final functional protein - isn't always occurring
- linked by covalent or non-covalent bonds
38
2nd structure of proteins
```
-alpha helix and beta pleated sheets
beta pleated sheets
-can be parallel or anti-parallel
-weak hydrogen bonds in backbone
-primary structure dictates whether it gets twisted in shape
```
39
1st structure proteins
-linear amino acid sequence, N-terminus (+) and C-terminus (-)
40
Sickle Cell Anemia
- red blood cells abnormally shaped
| - when sickled, cannot fit through capillaries
41
Polypeptide Chain
- side chains extend from peptide-bonded backbone
- chain is flexible, backbone is directional and asymmetrical
- starts at N-terminus
42
Peptide Bonds
- covalent bonds between amino acids
- created through condensation reaction
- joins carboxyl carbon to amino nitrogen
- allows bond rotation and peptide flexibility
43
Hydrophilic R Groups
- uncharged, but partial charges can form H bonds
- charged, groups containing acids or bases
- highly soluble in water
44
Hydrophobic R Groups
- no charged or electronegative atoms to form H bonds
- insoluble in water
- R groups bury themselves within polypeptide to 'hide' from water
- mostly C & H
- not very reactive
45
Hybrid Amino Acid
- ionized form
- increases solubility
- facilitates interactions with other amino acids/solutes
- increases reactivity
46
Amino Acids
1. small subunits of proteins
2. carboxylic acid & amino acid & r group
3. connected in linear polymers of specific sequences
4. 20 genetically encoded amino acid monomers
5. central carbon of amino acid is referred to as 'alpha' carbon
6. L-amino acids & D-amino acids, only L-amino acids are found in proteins
47
Hydrolysis Reaction
- chemical reaction in which water is added back across the bond
- separating larger molecule into smaller molecules
48
Condensation Reaction
-chemical reaction in which two or mole molecules combine and form water as a byproduct
49
Base
-substance that accepts protons resulting in a decrease of [H+]
50
Acid
-substance that gives up/donates protons resulting in increase of [H+]
51
the longer the bond...
the weaker the bond
52
water
- most abundant molecule in biological organisms
- known as universal solvent
- 2 types of interactions with compounds:
1. hydrophobic = water fearing
2. hydrophillic = water loving
53
H Bonds
- electrical attraction between electronegative atom and partial positive of hydrogen
- 3rd strongest in biological systems
54
Ionic Bonds
- ionic bonding
- ionization
- second strongest in biological systems
55
Covalent Bonds
- strongest bonds of biological systems
- two or more atoms share electrons...
1. equally - non-polar covalent bond
2. unequally - polar covalent bond, one atom has stronger pull on electrons than the other
56
4 atoms matter in organisms are made of (99%)
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
57
Regulatory Molecules
regulation of enzyme activity allows cell to control which enzymes are active at any time depending on the needs of the cell
58
3rd structure proteins
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-global structure (3-D)
twisted, coiled and folded into unique shapes
-ionic interactions
-hydrogen bonds
-disulphide bonds
-covalent bonds
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