Module 1 and 2 Flashcards
1
Q
Eukaryotic Cells
A
Plants and animals cells with a nucleus and membrane - enclosed organelles
2
Q
Prokaryotic Cells
A
unicellular organisms, without a nucleus or membrane-enclosed organelles.
3
Q
Functions of the plasma membrane:
A
maintains specific conditions for cellular function within the cell. Selectively permeable, therefore plays an important role in entrance and exit of substances. Carries markers that allows cells to recognise one another and can transmit signals to other cells via receptors.
4
Q
What differentiates bacterial cells?
A
Bacteria have no true nucleus
5
Q
Function of the cytoplasm
A
The interior portion filled with cytosol
6
Q
Function of Nucleus
A
Membrane-enclosed internal region that contains genetic material
7
Q
What are the main structures of the cytoplasm? (8)
A
Centrioles, cytoskeleton, lysosomes, mitochondria, peroxisomes, golgi apparatus, endoplasmic reticulum and ribosome.
8
Q
Function of ribosomes and where they are found
A
Ribosomes are the structures in which protein synthesis takes place. Found inbound in the cytoplasm, attached to the outer side of the nuclear membrane or attached to the ER.
9
Q
Functions of the endoplasmic reticulum
A
Delicate membrane structure, contiguous with nuclear membrane. Forms an extensive net of channels, and classified into smooth and rough types.
10
Q
Function of the rough ER
A
Lots of ribosomes attatched.
Synthesise and store proteins in ribosomes
11
Q
Function of smooth ER
A
No ribosomes.
Functions in diverse metabolic processes
Important for contraction stimuli in muscle cells
12
Q
Function of Lysosomes
A
Intracellular digestion through digestive enzymes.
13
Q
Explain autographic digestion
A
Occurs when residual substances of the cellular metabolism are digested
14
Q
Explain heterographic digestion
A
When substances that enter the cell are digested.
15
Q
How do lysosomes digest things?
A
Lysosomes enfold the substances, forming digestive vacuoles or residual vacuole, later fusing with the plasma membrane to release digested material to exterior.
16
Q
Function of mitochondria and where is it found
A
Organelles in which the most important part of cellular respiration occurs - ATP production - Krebs cell and the respiratory chain. Numerous in eukaryotic cells, particularly muscle cells. Can self-replicate.
17
Q
What is cellular respiration?
A
The process of using an organic molecule (mainly glucose) and oxygen to produce carbon dioxide and energy.
18
Q
About chloroplasts
A
organelles in plants in which photosynthesis occurs.
19
Q
What is photosynthesis?
A
The production of highly energetic organic molecules (glucose) from carbon dioxide, water and light.
20
Q
Function of plant cell wall
A
Structural and protective functions. Important role in limiting cell size and stopping cells from bursting.
21
Q
Function of vacuoles in plants
A
Osmotic balance of the intracellular space. Absorb and release water in response to cellular metabolic necessities.
22
Q
How does DNA use information?
A
DNA -> cell
DNA -> encodes genes -> encodes proteins
23
Q
Describe transcription
A
gene -> protein. Cell produces an intermediate molecule call messenger RNA (mRNA)
24
Q
Describe translation
A
Cell uses mRNA to produce protein.
25
Things in prokaryotes but not eukaryotes
No internal membrane
No nucleus
Naked DNA
26
Describe cytosol
Semifluid substance within cell
27
Define chromosomes
Carry genes in the form of DNA
28
Where does translation take place
Ribosomes
29
Cellular respiration formula
C6H12O6 + 6O2 = 6CO2 + 6H20 + ATPs
30
Where in plants is chlorophyll found?
In the plastids
31
Function of the cytoskeleton
A dynamic set of filaments
| For cell shape, support and movement
32
What do vacuoles contain?
enzymes, ions, pigments and toxic metabolic bby-products
33
What determines if something diffuses across a membrane?
- concentration gradient
- size
- charge/polarity/uncharged
- hydrophobic more likely to diffuse
34
Compare passive and active transport
```
Passive = osmosis, diffusion
Active = pumped across the membrane
```
35
What molecules can't diffuse, and how do they cross the membrane?
Na+, Cl-, K+. Must be TRANSPORTED
36
How are cells identified?
By protein markers. Receptor proteins interact with specific chemicals.
37
Explain the theory behind the fluid mosaic model
Phospholipids are AMPHIPATHIC molecules.
| Membrane is fluid with a 'mosaic' of proteins embedded in it
38
Compare hydrophilic and hydrophobic
Hydrophilic - water loving (head)
| hydrophobic - water hating (tail)
39
What does being amphipathic allow?
Ability to interact with both polar and non-polar substances
40
What do the energy levels of electrons do?
Partition the electrons into orbitals of different energy levels. Electrons with a higher energy state can sit further away from the nucleus.
41
Can electrons move from one shell to another?
Yes, but only if the energy it gains or loses is exactly equal to the difference in energy between the energy levels of the two shells.
42
Write the Aufbau principle
Electrons fill the lowest available energy levels before filling higher levels.
43
Write the Lazy Tenant Rule
Electrons at higher levels require higher energy to stay away from the nucleus
44
Write Hund's Rule
Where there is a choice, electrons fill the orbitals singly as far as possible, to minimise repulsion between electrons.
45
Whats the difference between the atomic and mass number
```
Atomic = number of protons
Mass = number of protons and neutrons
```
46
What are the naturally occuring elements in the human body?
Oxygen, Carbon, Hydrogen and Nitrogen
47
What is electronegativity?
ability of an atom to attract an electron to itself
48
What is electropositivity?
Willingness of an atom to give up an electron
49
How are covalent bonds formed?
Formed when two atoms share one or more pairs of electrons. DON'T LOSE BUT SHARE
50
How is a polar bond formed?
Molecule formed with electrons that have different electronegativities.
51
Define polar
One end of the molecule has the electrons near it more frequently.
52
What are the three weak interactions?
1. Ionic bonds
2. Hydrogen bonds
3. Van der Waals attractions
53
Describe ionic bonds
CHARGE TO CHARGE INTERACTIONS. Bonding due to force of attraction between a positive and negative ion. Ions formed because sometimes an interaction is more favourable if the valence electrons are completely stripped from one partner and given to the other.
54
How does water interact with charged ions?
By hydrating them. Water molecules orient themselves around the ions.
55
Explain Hydrogen bonds
An electrostatic attraction between an electronegative atom (O, N, F) and a Hydrogen atom attached to an electronegative atom.
56
Explain Van der Waals attractions
Instantaneous induced dipole - induced dipole. Occur over a very small and very defined distance. Not dependent on ionization or covalent bonding. The key is the oscillations of electrons around adjacent atoms.
57
What does the structure of water allow it to do?
Polar covalent bonds result in H bonding. Water is cohesive, and can act as a buffer. It can moderate temperature - the solvent of life.
58
Explain why/how water is a cohesive suubstance
3D networks of Hydrogen bonding in water holds molecules together making it a cohesive (sticky) substance.
59
How does water have high specific heat capacity?
The Hydrogen bonds are constantly being broken and reformed, making it resistant to heat change
60
Compare solution v solvent v solute.
A liquid that is a completely homogenous mixture of two or more substances is a solution.
The dissolving agent is the solvent.
The substance that is dissolved is the solute.
61
Why can polar and charged molecules dissolve in water?
Because they can interact with each other through polar bonding and other charge - charge interactions.
62
What will and won't dissolve in water.
WILL: polar molecules e.g. protein
| WON'T: non-polar molecules e.g. lipids
63
Avogadro's number
6.023 x 10^23
64
What happens to water when it dissociates (i.e. covalent partnerships are disrupted)
Results in hydronium ions and hydroxide ions
65
How is the acidity of a solution measured?
By the concentration of H3O+ ions present.
Higher the pH - lower the concentration of H3O+
Lower the pH - lower the concentration of H+
66
Explain the carbonic-bicarbonate system
Major buffer system in the body. CO2 is carried to the lungs for elimination or is dissolved in body fluids - forming carbonic acid (H2CO3) that dissociates, the the freed proton reassociates with water to produce bicarbonate ions (HCO3--) and Hydronium ions (H3O+).
67
Write the equation for the carbonic - bicarbonate system
H2CO3 + H2O HCO3- + HCO3+
68
What does the buffer system do with protons?
Soaks them up and locks them into a relatively stable compound.
69
What is molarity versus moles
Molarity is an expression of concentration, whilst moles indicate absolute numbers of molecules.
70
How do acid and bases relate to protons?
Acids are proton donors and a base is a proton acceptor.
71
Characteristics of proteins
Lots of nitrogen, not phosphorous
72
Characteristics of carbohydrates
Hydrated carbons - i.e. with things that make water (H & O)
73
What characteristics of lipids make them identifiable?
lots of carbon, lots of hydrogen - few oxygens
74
What do lipids do?
- Energy storage
- Insulation and protection
- Digestion and absorption
- Nutrition
- Cell membrane structures
- Hormone production
75
Compare viscous and fluid in regards to the plasma membrane
Viscous - all the tails are packed together
| Fluid - fewer molecules, making the tails kinked
76
What does cholesterol do in the plasma membrane?
It's embedded in various layers and acts as a buffer against body temperature.
77
How do the integral membrane protein affect the plasma membrane?
Protein structure determined by amino acid sequence and how the side chains are making up membranes
78
What are the major functions of the plasma membrane?
- transport
- enzymatic activity
- signal transduction
- cell-cell recognition
- intercellular joining
- attachment to cytoskeleton
79
What are lipid bilayers impermeable to?
most essential molecules and ions, K+, Ca2+ Na+ Cl- HCO3-
80
Define tonicity
The ability of a solution to cause a cell to gain or lose water.
81
define hypertonic solution
Solute concentration is greater then inside the cell. CELL LOSES WATER
82
Define hypotonic solution
Solute concentration is less then inside the cell. CELL GAINS WATER
83
Describe osmosis
Molecules in solution cannot cross the membrane, so water moves to find equilibrium.
84
Define osmolarity?
How many particles the compound becomes when it dissolves
85
Define facilitated diffusion
Passive transport aided by a protein
86
What do transport proteins do in facilitated diffusion and what are the two types
Speed up the passive movement of molecules, allowing the passage of hydrophobic molecules. Channel proteins and carrier proteins.
87
What detail of proteins is important in channel proteins?
Shape - so compound can be processed
88
Describe carrier proteins
Open to extracellular environment, then changes shape to allow an ion to enter the membrane
89
In what direction does facilitated diffusion flow and does it require energy?
Occurs along the concentration gradient and doesn't require energy.
90
What are water channels called?
Aquaporins.
91
What are gated channels
Aquaporins and ion channels that open or close in response to a stimulus
92
Whats an electrogenic pump?
A transporter that generates voltage across a membrane
93
what is the main electrogenic pump in animals?
The sodium-potassium pump
94
What is a mutant?
Any organism that has a genetic sequence that differs from the wild type.
95
How is a nucleic acid bonded together?
Covalently bonded together forming a stable structure
96
What does the statement 'DNA replication happens semi-conservatively' mean?
One strand is maintained in its original form and used as a template for the production of a new strand - always replicates both strands.
97
What does 'DNA has one direction' mean?
Bases are added from one end of the chain; from the 3' end. DNA has a leading and a lagging strand during replication.
98
What does transcription involve?
The initiation, elongation and termination stages. Makes RNA from a DNA template.
99
Describe initiation
RNA polymerase binds to the promoter, DNA strands unwinds and polymerase initiates RNA synthesis.
100
Describe elongation
Polymerase moves downstream, unwinding the DNA and elongating the RNA transcript 5' - 3'. DNA strands re-form a double helix
101
Describe termination
RNA transcript is released and the polymerase detaches from the DNA
102
What happens after transcription?
RNA used as a template for translation
103
Describe translation
Eukaryotic RNA processed before translation, splicing out introns and keeping exons to make the finishes mRNA. Sequence read in triplet codes (Codons). Proteins produced when the ribosome translates the RNA sequence to make a protein. Proteins trafficked to ER if they are going to be membrane bound, lysosomal or secreted. Ribosomes stick to ER due to signal sequencing in the protein chain.
104
Write a simple summary of the central dogma
DNA goes to mRNA goes to protein
105
How do proteins bind to their interaction partners?
Through shape matching
106
Whats an intron
a non-coding region
107
What are four examples of non-spontaneous reactions that need energy to occur?
- maintaining homeostasis
- Synthesis of large macromolecules
- Emitting light and sound
- Moving
108
What is ATP breakage used for?
To power anabolic reactions and non-spontaneous processes in cell and body metabolism
109
What is the first part of the respiratory pathway
Glycolysis in the cytoplasm
110
What is broken in phosphorylation?
Glucose from the blood which is trapped in the cell
111
Explain what happens in the Glycolysis Energy Investment Phase
Two ATPs are consumed to prepare glucose for breakage. Phosphorylated glucose then broken into two three carbon sugars. Payoff phase of glycolysis then begins,
112
Draw the Glycolysis energy payoff phase
Glycolysis -> Pyruvate oxidation OR Oxidative phosphorylation OR ATP
Pyruvate oxidation -> Citric acid cycle -> oxidative phosphorylation OR ATP
Oxidative phosphorylation -> ATP
113
What forms of energy can you harvest from respiration
NADH, ATP and FADH2
114
Explain what happens when pyruvate is transported to the mitchondria
It's converted into Acetyl CoA, generating NADH as 2 electrons are harvested from glucose - used to generate ATP. Carbons and Oxygens from glucose begin to be discarded as CO2
115
What happens to Acetyl CoA when it's fed into the citric acid cycle
For each glucose that enters glycolysis, two acetyl CoA are fed into the TCA cycle; producing 6 NADH, 2 FADH2 and 2 ATP for each glucose that enters glycolysis and the TCA cycle produces 4 CO2. NADH and FADH2 synthesise more ATP
116
What does the electron transport train do?
Uses electrons from NADH and FADH2 to pump protons into the mitochondrial IM space. At the end of the chain, Oxygen accepts the electrons and combines with a proton to make water.
117
What kind of process is respiration?
A multi-step process that cells use to extract energy from biomolecules so that the energy can be used to fuel multiple processes in the body. Many different molecules can be used by the cell to feed into this process but glucose is the preferred substrate for the pathway.
118
What waster products are produced from the breakdown of glucose?
CO2 and H2O
119
What are the three kinds of local signalling?
1. Autocrine (with its self)
2. Paracrine (more the one)
3. Synaptic (neurotransmitters released in the synapse)
120
What are the two kinds of long distance signalling?
1. Endocrine: secret hormones to body fluids. They reach most body cells but only effect some cells.
2. Nerve: electrical activity in neurons
121
What is stage 1 of signalling
RECEPTION
| Signalling molecules goes to the receptor which it fits into
122
What is stage 2 of signalling
TRANSDUCTION
| Three relay molecules in a signal transduction pathway
123
What is stage 3 of signalling
RESPONSE
| Activation of cellular response
124
What are the three types of plasma membrane receptors?
- Ion channel linked receptors
- G protein-coupled receptors
- Tyrosine kinase linked receptors
125
Describe an ion channel linked receptor
Fastest working response, in miliseconds, Na+ channel opened by ligand
126
Describe G-protein coupled receptors
7 Transmembrane spanning regions. Occurs in seconds
Largest family of receptors: >1000 members in human genome, 150 organs.
Activated by a variety of stimuli
127
Describe Tyrosine Kiinase linked receptors
Minutes to occur. e.g. insulin receptors. Roles in metabolism, cell growth and cell reproduction.
1 transmembrane
128
Describe and name the one intracellular receptor
Steroid receptors - slowest working responses (hours - days)
129
What is the role of protein phosphorylation
add negative ions -> conformation change shape, protein-protein interactions, change in cellular location
130
Describe electrical synapses
tight gaps, hence able to transmit electrical signals - direct electrical currents between cells.
Relatively few synapses of this type
131
Chemical synapses
Release of chemical neurotransmitter from presynaptic neuron.
Vast majority of synapses
132
Define endocytosis
Molecules go into little sac which then breaks off into a vesicle
133
Define exocytosis
Vesicles bond with cell membrane to open and release molecules - neurotransmitter release at chemical synapse.
134
Describe what happens at the Ca2+ channels
VOLTAGE GATED CHANNEL
Opens due to depolarising event
Ca2+ ions move into cell due to concentration gradient
Allows vesicles to move to cell membrane causing transmitter to be released -> acts on receptors to produce effect on nest neuron
135
What does EPSP stand for and what happens there?
Excitory postsynaptic potential if depolarisation at postsynaptic membrane
136
What does IPSP stand for and what happens with it?
Inhibitory Postsynaptic Potential if hyperpolarisation at postsynaptic membrane.
137
What is temporal summation and what can it make happen?
Several EPSPs from the same synapse just after each other. Synapse can reach threshold at axon hillock - ACTION POTENTIAL
138
What is spatial summation?
Two or more EPSPs from different synapses.
139
What are the four factors of postsynaptic potential?
- excitory or inhibitory (hyperpolarisation)
- graded
- local
- - At the cell body or dendrites
140
what are the five factors of action potential?
- depolarisation
- "all or nothing"
- Excitatory postsynaptic potentials can add up and cause an action potential
- generated at the axon hillock
- travels along the axon
141
Describe direct synaptic transmission
- Ion channel linked channel
- neurotransmitter opens ion channels on the postsynaptic membrane - leads to a postsynaptic potential
- action in Ligand-gated ion channels
142
Describe indirect synaptic transmission
- Neurotransmitter binds to a receptor on the postsynaptic membrane
- Activate a signal transduction pathway
- Involves a second messenger
* G-PROTEIN-COUPLED RECEPTORS*
- Can results in EPSP or IPSP
143
How are neurotransmitters removed?
- diffuse away
- broken down by enzymes
- recycled by selective uptake transporters
144
What are the three stages of information processing
1. Sensory output (PNS) sensor
2. Integration (CNS)
3. Motor output (PNS) effector
145
Function of dendrites
- Bring in information from many other nerve cells into cell body of neuron
146
Function of axon
Information to axon hillock -> action potential initiated -> travels down axon
147
Function of synapse
Chemical release
148
Structure of sensory neuron
Cell body along axon
149
Structure of interneuron
Collect lots of info, dense dendritic tree, more branched axon, more interaction
150
Structure of motorneuron
most common, long axon
151
What is a nerve
Many axons supported by connective tissue with blood vessels to supply nutrients and remove waste
152
What are GLIA
Supporting cells - vital for structural integrity and normal function
153
What are the two types of GLIA cells
1. Astrocytes
| 2. Oligoodendrcytes and schwann cells
154
Describe Astrocytes
- CNS
- Structural support
- Regulate extracellular concentration of ions and neurotransmitters
- blood brain barrier
155
Function of Oligoodendrcytes (CNS) and schwann cells (PNS)
Form myelin sheaths
| Insulators
156
What amounts of ions does the Na+/K+ electrogenic pump pump?
3 Na+ out of cell
2 K+ into cell
Creates net -ve charge of inside of cell
157
What is equilibrium potential in a neuron
-70mV
158
Define membrane potential
Voltage of inside of membrane relative to outside - equilibrium
159
Hyperpolarisation
Inside of membrane becomes more negative
- Opening of voltage-gated K+ channels
- K+ out
160
Depolarisation
Onside of membrane becomes positive
- Opening of voltage gated Na+ channels
- Na+ in
161
What happens during absolute repolarisation
No AP generated. Na+ channels open then inactivated
162
What happens during relative repolarisation
AP only if apply large stimulus. Some Na+ channels closed again
- Limits firing frequency
- Action potential only in one direction
163
How do local anaesthetics work?
Prevent action potentials by blocking voltage-gated Na+ channels
164
How does axon diameter affect AP conduction speed
- Larger the diameter, less resistant FASTER
165
How does temperature affect AP conduction speed
Occurs faster at warmer temps
166
How does degree of myelination affect AP conduction speed
Myelin insulin = faster conduction speed
167
How does being myelinated and unmyelinated affect conduction speeds
```
Unmyelinated = smooth conduction
Myelinated = Saltatory conduction
```
168
How many cranial and spinal nerves are there in mammals?
```
Cranial = 12
Spinal = 31
```
169
What are the two possible reflex arcs?
Sensory neuron -> motorneuron
| Sensory neuron -> interneuron -> motorneuron
170
Explain whats involved in the somatic PNS
Motor neurons - voluntary
171
Explain the kind of reactions from the sympathetic division of the autonomic PNS
- "fight or flight"
- bronchi dilate
- heart beats faster
- glycogen to glucose
- adrenaline secretion
- digestion is inhibited
172
Explain the kind of reactions from the parasympathetic division if the autonomic PNS
- "Rest and digest"
- Calming
- Often opposite response to sympathetic division
173
What is the grey matter and white matter in the brain
Grey on outside - dendrites, unmylinated axons, cell bodies
White on inside - myelinated, axons the trats
OPPOSITEE TO THIS IN SPINAL CORD
174
What are the functions of the brain stem
- Basic functions
- Homeostasis, movement
- transfers info to rest of brain
- Reticular formation
175
Functions of the CEREBRUM
- motor function
- coordination
- Cognitive and perceptial functions
176
Dincenphalon
- motor function
- Coordination
- Cognitive and perceptral functions
177
Epithalamus
- Connects limbic system
| - Pineal gland - sleep
178
Thalamus
- input from sensory neurons
| - Output via motor neurons
179
Hypothalamus
- Homeostatic regulation
- Biological clock
- Temp. regulation
- Survival - hunger, thirst
180
Cerebrum
Left and right hemisphere
- cerebral cortex
- corpus callosum
- communication between L & R
- Important for movement
181
What are the four lobes of the brain
Frontal
Parietal
Temporal
Occipital
182
What are the stages of memory and where they are stored in the brain?
Short term: constantly active, Hippocampus
Long term: Cerebral cortex
Time to remember: short-term activated again
