unit one Flashcards
(74 cards)
1
Q
what are the basic qualities about cells?
A
- cells can vary in size and structure
- can be both an organism and part of an organism
- multiple cells make up specialized tissues and organs
- unicellular organisms have to carry out all the functions with their one cell
- most cells are self-replicating, with the exception of neurons, gametes, and red blood cells
2
Q
what does self-replicating mean?
A
cells reproducing themselves to create an identical copy
3
Q
what are the criteria for a cell to be self-replicating?
A
- have DNA and a way to replicate it
- a way to read the DNA
- energy source
- raw materials
- plasma membrane
- way to replicate other organelles and cell materials
4
Q
what is the cell theory?
A
1) all living organisms are made up of cells
2) cells are the basic unit of life
3) cells arise from pre-existing cells
4) hereditary info is passed from cell-to-cell
5) all cells have the basic chemical composition
6) energy flow occurs within cells
5
Q
what is a prokaryotic cell?
A
they have no membrane-bound organelles
6
Q
what is a eukaryotic cell?
A
they have membrane-bound organelles
7
Q
what is the main differences between prokaryotic and eukaryotic cells?
A
- eukaryotes have membrane bound organelles
- prokaryotes have no mitochondria, or nucleus
- prokaryotes are smaller than eukaryotes
- prokaryotes are more primitive than eukaryotes
- prokaryotes have circular DNA present in the nucleoid, eukaryotes have linear DNA present in the nucleus
8
Q
what are the types of bonds?
A
- covalent bonds
- non-covalent bonds
- polar covalent bonds
9
Q
what is a covalent bond?
A
intramolecular bond
stronger and more permanent
10
Q
what is a non-covalent bond?
A
intermolecular bond
weaker and less permanent
lots of non-covalent bonds hold molecules together
11
Q
what is a polar covalent bond?
A
unequal sharing of electrons due to a difference in electronegativity
12
Q
what is the electronegativity scale order?
A
O > N»_space; S > C = H = P
13
Q
if a molecule is polar, is it hydrophilic or hydrophobic?
A
hydrophilic
14
Q
if a molecule is non-polar, is it hydrophilic or hydrophobic?
A
hydrophobic
15
Q
what is the main type of non-polar bond?
A
C-H bond
16
Q
what is an induced dipole?
A
non-polar
17
Q
what is a permanent dipole?
A
polar
18
Q
what is the basis of organic molecules?
A
must have at least 1 C-H bond
19
Q
what are the 4 major macromolecules?
A
- carbohydrate
- protein
- nucleic acid
- lipid
20
Q
what are carbohydrates used for?
A
energy source
21
Q
what are proteins used for?
A
enzymes, structure, support
22
Q
what are nucleic acids used for?
A
DNA and RNA
23
Q
what are lipids used for?
A
cell membrane
24
Q
what three macromolecules exhibit polarity?
A
carbohydrates, proteins, and nucleic acids
25
what does polarity mean in terms of macromolecules?
the polymer has two chemically distinct ends
26
what is the general structure of a protein?
- N terminus and C terminus
- alpha carbon
- R group
27
what is the directionality of a protein?
N to C
28
what is the monomer of proteins?
amino acid
29
what is the bond in a protein called?
peptide bond
30
what is the general structure of a nucleic acid?
- phosphate group
- 5 carbon ring
31
what is the directionality of a nucleic acid?
5' to 3'
32
what is the monomer of a nucleic acid?
nucleotide
33
what is the bond in a nucleic acid called?
phosphodiester bond
34
what is the monomer of a carbohydrate?
monosaccharide
35
what is the bond in a carbohydrate?
glycosidic bond
36
why are lipids different?
they are defined by their properties more than their structure
(typically very hydrophobic)
37
what is the monomer of lipids?
fatty acids
38
what is the bond in a lipid?
ester linkage
39
what is the general structure of a lipid?
a non-identical molecule (head group) attached to the monomer chains (tail)
40
what is the general structure of a phospholipid?
- two non-polar hydrophobic fatty acid tails
- polar, hydrophilic, phosphate head
- glycerol backbone
41
what are the three types of phospholipid arrangements? describe each.
- bilayer: smaller head, double tails
- liposome: mixed lipids, some double tails
- micelle: bulkier head, single tail
42
what is molecular self-assembly?
when molecules form a particular 3D conformation or structure
43
why does molecular self-assembly occur?
1) interaction with surrounding water molecules
2) intermolecular interactions
3) intramolecular interactions
- it is more thermodynamically favourable to be in that structure
44
describe phospholipid self-assembly in water.
- spontaneous (self-healing)
- energetically favourable
- gibbs free energy is less than 0
- system shifts from less stable to more stable
45
what is the hydrophobic effect?
allowing hydrophobic / non-polar molecules to clump together thereby increasing the entropy of the water
46
what is the largest contributor to bilayer stability?
although both entropy and enthalpy contribute to bilayer stability, entropy is the largest contributor
47
what does it mean by the selective barrier of the cell membrane?
the lipid bilayer of semi-permeable, it has a selective barrier - only allows small, non-polar molecules through.
48
why does the cell have a selective barrier?
to help maintain homeostasis
49
what are the 2 types of transport?
passive and active
50
what is passive transport?
- diffusion
- goes along the conc gradient
- no input of energy
- move in both directions
51
what are the two types of diffusion?
simple diffusion and facilitated diffusion
52
what is simple diffusion?
diffusions through the bilayer
53
what is osmosis?
the diffusion of water to make the conc of solute equal
54
what is facilitated diffusion?
uses a transport protein to diffusion across the bilayer. can be with a channel protein, or a carrier protein
55
what is facilitated diffusion using a channel protein?
- open or gated
- diffuse through the channel
- for ions and small polar/ non-polar molecules
- hydrophilic pathway
- faster than carrier mediated
- molecules interact with protein for it to be transported
56
what is facilitated diffusion using a carrier protein?
- gated
- more specific than channel proteins
- protein undergoes conformational changes to open and close the protein
57
what is active transport?
requires energy to go against the concentration gradient. there is primary and secondary
58
what is primary active transport?
- energy is required to directly move a molecule from one side of the membrane
59
what is secondary active transport?
- energy is required to build up the concentration of different molecules
- creates an electrochemical gradient
- diffusion of the molecule along the gradient is used to power the movement of the molecule
- ATP used to pump H+ out
60
how is the bilayer described as?
fluid mosaic model
61
what are integral membrane proteins?
permanently associated with the cell membrane and cannot be separated from the membrane experimentally without destroying the membrane itself
- most are transmembrane proteins (span the entire bilayer)
- embedded in the membrane
62
what are peripheral membrane proteins?
temporarily associated with the lipid bilayer or with integral membrane proteins through non-covalent interactions
- easily separated
- associated with either the internal or external side
- not embedded in the membrane
63
what is a peptide?
short chain of <50 amino acids
64
what is a polypeptide?
long chain of amino acids
65
what is a protein?
folded chain of amino acids
66
what is amino acyl residue?
amino acids with either H or OH removed in the process of peptide bond formation
67
what is the backbone of an amino acid?
everything but the R group
- atoms that make up the covalent linkages from one amino acid to the next
68
what does the sequence of amino acids decide?
sequence - structure - function
69
what are the four levels of structures for a protein?
primary, secondary, tertiary, quatrenary
70
what is primary structure of a protein?
- sequence of amino acids
- ultimately dictates function
71
what is the secondary structure of a protein?
- results from interactions of nearby amino acids
- interaction between backbone
- stabilized by hydrogen bonds between backbone
- 2 types: alpha helices and beta sheets
72
what is the tertiary structure of a protein?
- 3D structure (fold) of entire polypeptide stabilized by side-chain interactions (non-covalent and disulfide) as well as interactions between sidechains and backbone
- when it truly becomes a protein
73
what is quatrenary structure?
- multiple folded polypeptide chains
- stabilized by non-covalent interactions
- not all proteins have this structure
74
what is protein denaturation?
a change in temp, pH, etc. that will cause a protein to unfold
