Module 1 Flashcards
(143 cards)
1
Q
Polymer
A
A long molecule consisting of many similar or identical building blocks linked by covalent bond
2
Q
How are monomers linked to each other
A
Condensation reactions (2 molecules are covalently bonded to each other with the loss of another smaller molecule)
3
Q
What is a condensation reaction called if water is lost
A
Dehydration reaction
4
Q
How do polymers become monomers
A
Hydration reaction
5
Q
Hydration reaction
A
Bond between monomers are broken by the addition of a water molecule with a hydrogen from water attaching to one monomer and the hydroxyl group attaching to the other
6
Q
Carbohydrates
A
Sugars and polymers of sugars
7
Q
Assymetric carbon
A
Carbon attached to 4 different atoms or groups of atoms
8
Q
Monosaccharides
A
Class of sugars that cannot be hydrolysed to give a simpler sugar
9
Q
How is diversity amongst sugars created
A
The way their parts are arranged spacially around assymetric carbons changing shape and binding activities of the sugar
10
Q
Functions of monosaccharides
A
Major nutrients of cells, their carbon skeletons serve as raw material for the synthesis of other types of small organic molecules such as amino acids or fatty acids
11
Q
Monosaccharides with 5 carbons
A
Pentose sugars
12
Q
Monosaccharides with 6 carbons
A
Hexose sugar
13
Q
A
14
Q
Disaccharide
A
Double sugars (2 monosaccharides joined covalently), must be broken down into monosaccharides to be used as energy
15
Q
Polysaccharides
A
Few 100 to thousands of monosaccharides joined by glycosidic linkage
16
Q
Some functions of polysaccharides
A
Storage material hydrolysed as needed, building blocks for structures that protect the cell or organism
17
Q
Storage polysaccharides (animals and plants)
A
Plants - starch a polymer of glucose monomers as granules stored in plastids
Animals - glycogen, a polymer of glucose stored mainly in muscle of liver cells
18
Q
Structural polysaccharides
A
Cellulose - major component of the tough cell wall of plants, indigestible as we don’t possess the enzyme to breakdown
19
Q
How is cellulose different from starch and glycogen
A
Arrangement of monomers, amount of binding between monomers
20
Q
Lipids
A
Class of biological molecules that are non-polymeric, generally not big enough to be considered macromolecules.
21
Q
How are lipids grouped
A
All share trait of being hydrophobic due to molecular structure
22
Q
Types of lipid
A
Fat (triaglycerol)
Fatty acid
Phospholipids
Steroids
23
Q
Fats (triaclyglycerol)
A
Large molecules assembled by smaller molecules by dehydration reactions
24
Q
Fats chemical structure
A
A glycerol molecule joined to 3 fatty acids
25
Function of fats
Energy storage (double as much energy as polysaccharides)
26
Fatty acid
Long carbon skeleton usually 16-18 carbon atoms in length
27
Phospholipids structure
2 fatty acid tails and the 3rd hydroxyl group of glycerol is joined to a phosphate group
28
Properties of phospholipid
Hydrocarbon tails are hydrophobic, phosphate group form a hydrophobic head
29
Steroids structure
Lipids characterised by a carbon skeleton consisting of 4 fused rings
30
What factors influence lipid fluidity
Saturation, temp, cholesterol
31
How does saturation influence lipid fluidity
Saturated = tightly packed = less fluidity
Unsaturated = tails prevent tight packing
32
How does temp influence fluidity
High temps = more fluid
33
Influence of cholesterol on fluidity of membrane
Stabilises membrane fluidity, by stopping membrane from getting too fluid when temp goes up
34
Membrane protein functions
Signal transduction
Cell recognition
Intracellular joining
Linking cytoskeleton and ecm
Membrane transport
35
Membrane protein- signal transduction
Relay messages from body into cell
- grow, divide, make something, die etc
36
Membrane proteins - cell recognition
Often involves glycoprotein
37
Glycoproteins
Proteins with added sugars
38
Membrane proteins - intracellular joining
Some proteins form long lasting connections with other cells
39
Membrane proteins - linking cytoskeleton and ecm
Allows for cells to physically connect with protein structures outside the cell
40
Co-transport
Indirect active transport, one substance pumped across membrane using energy against gradient, which will then follow conc gradient and bring another molecule through second protein passively
41
What do organelles allow for
-provide special conditions for specific processes
- keep incompatible processes apart
- allow for specific substances to be concentrated
- package substances for transport/export
42
Smooth er functions
-Metabolise carbohydrates
- lipid synthesis for membrane
- detoxification of drugs and poisons
- storage of calcium ions (for use as a signal)
43
rER
Ribosomes involved in protein synthesis
Secreted and membrane bound protein enter lumen (interior) and are processed
44
Where do transport vesicles arrive and leave the golgi
Vesicles arrive at cis and processed vesicles leave trans
45
Glycolisation at golgi
Addition or modification of carbohydrates to proteins
46
Function of golgi
Produce Polysaccharides that may be secreted from cell, sorting proteins, directing vesicle trafficking
47
48
How does the Golgi sort proteins
Adding molecular markers to direct proteins to the correct vesicles before budding from trans face
49
How does Golgi direct vesicle transport
Adds molecular tags (short proteins exposed on vesicles surface), to vesicles to direct them to correct targets and act as docking sites when they reach target
50
Vacuoles
Large vesicles derived from rER and Golgi
51
Function of vacuoles
Absorbs water allowing plant cells to grow without a large increase in cytoplasm and can preform lysosome like functions
52
Constitutive exocytosis
Release ecm proteins
53
Regulated exocytosis
Release hormones and neurotransmitters - only happens among signal
54
Receptor mediated endocyyosis
Specialised form of pinocytosis, allows cell to take up bulk quantities of specific substances which may be present at low concentrations in extracellular fluid, receptor proteins are used to selectively capture required substance
55
Lysosomes
Made by rER and Golgi containing hydrolytic enzymes, internal env is acidic
56
Lysosome function
Degrade proteins, lipids, carbohydrates, and nucleic acids and release breakdown products into cell for recycling
57
Autophagy
The process in which lysosomes digest unwanted cellular materials
58
Function of cytoskeleton
Maintain shape and position of organelles, allows for rapid changes in cell shape
59
How does the cytoskeleton allow for rapid changes in cell shape
Cytoskeleton rapidly disassembles and reassembles, meaning it is highly dynamic
60
Three main components of cytoskeleton
Microtubules, micro filaments, intermediate filaments
61
Function of microtubules
Resist compression and tension, cell and organelle motility
62
63
Microtubules structure
Composed of tubulin subunits which forms spiral shape, and may radiate from centrosome (organising centre)
64
Microfilaments function
Strong, good tension
65
Microfilaments structure
Double actin subunits organised like a rope forming either linear strands or 3d networks (cortical network)
66
Intermediate filaments function
Forms relatively permanent cellular structure (maintain cell shapes and anchor organelles), may remain after cell dies
67
Intermediate filaments structure
Really tightly packed, supercoiled into proteins, e.g. keratins, lamins, neurofilaments (depends on cell)
68
Types of cell junctions
Tight, gap, desmosomes
69
Components of cytoskeleton based on size (big-small)
Microtubules, intermediate filaments, Microfilaments
70
Tight junctions function
Hold neighbouring cells tightly pressed together, preventing fluid movement between cells
71
Tight junction structure
Anchored to actin (Microfilaments)
72
Desmosomes function
Provides attachment between sheets of cells (e.g. muscles), anchoring junction
73
Desmosomes structure
Intermediate filaments
74
Gap junction function
A site of cytoplasmic contact btw 2 cells allowing for rapid cell to cell communication and ions and small molecules
75
Ecm composed of mainly
Glycoproteins
76
Most concentrated glycoprotein in ecm
Collagen
77
How is collagen embedded in ecm
Embedded in proteoglycan matrix
78
Purpose of proteoglycans in ecm
Trap water which helps to resist compression and retain tissue shape
79
How are cells attached to ecm
Glycoproteins in particular fibronectin
80
How is the ecm connected to cytoskeleton
Membrane proteins, in particular integrins
81
Function of integrins
Provide communication link btw ecm to cells interior
82
Major energy requirements of the cell
-mechanical work (motor proteins)
- to make new materials (growth and replacement)
- transport (across a membrane)
- to maintain order
83
Structure of mitochondria
Contains mtDNA, ribosomes, has 2 membranes
84
Mitochondrial structure (out to in)
Outer membrane, inter membrane space, cristae (inner membrane), matrix
85
What happens in glycolysis
Glucose 6 carbon molecule is converted to 2 puruvate molecules (3 carbon), producing an output of 2 ATP and loading NADH
86
Where does glycolysis occur
In cytosol of cell
87
What is the second stage of cellular respiration
Pyruvate oxidation and citric acid cycle
88
Pyruvate oxidation
2 pyruvate molecules are converted to acetyl co enzyme A, also producing 2 CO2 and 2 NADH
89
Where does pyruvate oxidation and citric acid cycle occur
Mitochondrial matrix
90
Output of stage 2 of cellular respiration
8 NADH, 2 FADH2, 2 ATP AND 4 CO2
91
What are the 2 steps to oxidative phosphylaration
ETC and chemiosmosis
92
What happens in etc - oxidative phosphorylation
Electrons from NADH and FADH2, shuttle high energy electrons to the cristae, these electrons move through protein complexes into matrix, the movement of these h+ ions create a proton gradient
93
What happens in chemiosmosis - oxidative phosphorylation
The cristae contains ATP synthase, protons move following gradient through ATP synthase loading ADP+Pi to ATP
94
Inputs and outputs cellular respiration
Inputs - glucose and oxygen
Output - co2 water and atp
95
How many membranes does a chloroplast have
3
96
Three compartments of chloroplast
Intermembrane space, stroma and thylakoid space
97
What occurs in light reactions
Light energy excites chlorophyll, splitting water, releasing o2 and 2h+ ions, electrons move down electron transport chain, loading NADPH, and creating a proton gradient, with large amount of h+ ions inside the membrane, and then chemiosmosis as they move through ATP synthase
98
Calvin cycle steps
Fixation
Reduction
Regeneration
99
Fixation - Calvin cycle
3 x 5 carbon molecule (rubisco) + 3 CO2 makes 6 phosphoglycerate (3 carbon molecules)
100
Reduction - Calvin cycle
6 phosphoglycerate (3 carbon) which are low energy use 6 atp and 6nadph to form 6 high energy 3 carbon molecules called glyceraldehyde 3-phosphate, one of which will be an output of the Calvin cycle
101
102
Regeneration - Calvin cycle
5 glyceraldehyde molecules (3 carbon) use 6ATP to form 3 rubisco molecules (5 carbon)
103
How many glyceraldehyde 3 phosphate are required for one glucose
2 as glucose is a hexose sugar (6 carbon)
104
Cell wall phases
- microfibrils (crystalline phase)
- matrix (non-crystalline phase)
And a network of extensin
105
What is the most importing structural component of cell walls
Cellulose
106
Structure of cellulose
Highly ordered glucose polymer, that has a long ribbon like structure and is indigestible due to a tightly bound chemical structure
107
Cellulose forms
Microfibrils
108
Hemicellulose structure
Heterogenous group of polysaccharides, long chain of one type of sugar and short side chains
109
Where does the long chain of hemicellulose run in the cell wall
Lay along the microfibril
110
What does the short side chain of hemicellulose do in plant cell wall
Acts as a binding structure
111
Hemicellulose acts as … in plant cell wall
Connecting rods
112
Pectin structure
Branched, negatively charged polysaccharides that hold and bind water and have gel like properties
113
Where is pectin found in cell walls
Infused amongst microfibrils
114
Function of extensin in cell walls
Expansion of cells
115
Extensin cross linking of pectin and cellulose…
Dehydrates the cell, reduces extensibility, and increases strength
116
More extensin =
Less expandable
117
Where are cellulose microfibrils synthesised
Plasma membrane
118
Where are the polysaccharides (pectin and hemicellulose) synthesised
Golgi complex, and transported to the plasma membrane in vesicles
119
Where is glycoprotein (extensin) synthesised
Rough ER
120
How is the primary cell wall synthesised (cellulose)
Cellulose producing rossettes (cellulose synthase) are protein complex’s that span the plasma membrane, each producing one strand of cellulose which join to form microfibrils
121
Primary cell wall is composed of
Cellulose microfibrils, polysaccharides (pectin and hemicellulose) and glycoproteins (extensin)
122
Where are cellulose producing rosettes (protein complexes) found
Lay parallel to cortical microtubules, and span the plasma membrane
123
Relationship btw position of microfibrils and microtubules in plants
Cellulose producing rosettes lay parallel to cortical microtubules, therefore by moving the position of microtubules you can influence the position of cellulose microfibrils
124
How does the orientation of cellulose microfibrils influence cell morphology
Random - cell will expand equally in all directions
Right angles to the ultimate long axis of cell- cell will expand longitudally along that axis
125
Middle lamella
Region btw 2 cell walls and is highly concentrated in pectin
126
Hypertonic solution =
Shriveled cell
127
Secondary cell wall function
Thicker and stronger than primary cell wall, provides more structural support
128
Structure of secondary cell wall
Made of multiple layers, microfibrils of diff layers have diff orientations
129
Chemical diff between first and second cell wall
Secondary cell wall has more cellulose less pectin and lignin
130
Lignin (second most abundant organic molecule)
Complex polymer, that acts to exclude water
131
Lignin function
Confers strength and rigidity
132
Plasmodesmata
Intracellular connections that enable cell to cell communication, allows exchange of small molecules
133
How do plasmodesmate form
Parts of ER stay in pores during replication
134
Nuclear lamina
Lines the inner surface of nuclear envelope, composed of intermediate filaments
135
Nuclear lamina function
Maintains shape of nucleus, helps to organise packing of DNA
136
Structure of nucleus
Surrounded by nuclear envelope which has nuclear pores, has prominent area called nucleolus
137
Nuclear envelope structure
Phospholipid bilayer membrane with a perinuclear space in between, the outer membrane is continuous with ER
138
Nuclear pores
Channels made of proteins (nucleoporins)
139
Nucleolus function
Making rRNA and ribosomal subunits
140
141
DNA organisation in nucleus
DNA double helix interacts with his tines (h2-h4) forming a 10nm diameter fibre (nucleosome) then interactions with h1 causes it to coil which then loops to form a 100 nm fibre
142
Euchromatin
Contains genes being used by that cell, less electron opaque
143
Heterochromatin
Contains genes not being used by that cell, more electron opaque
