Biology Unit 1

?
  • Created by: danielle
  • Created on: 08-04-19 16:42
What is a Proteome?
The Proteome is the entire set of proteins expressed by a genome.
1 of 108
Why is the Proteome larger than the number of genes (genome)?
This is due to Alternative RNA Splicing and Post Translational Modification
2 of 108
Describe the Structure of Proteins
Folded Nature, Bind tightly to Molecules, Must be Folded in a Specific Manner to allow them to function properley
3 of 108
What do Amino Acid Sequences do?
Determine Protein Structure
4 of 108
Name the 4 Different Types of Amino Acids
Acidic (-), Basic (+), Polar (Hydrophilic) & Non-Polar (Hypodrophobic)
5 of 108
Describe the Primary Structure of Proteins
The order in which the amino acids are synthesised into thhe polypeptidechain
6 of 108
Describe the Secondary Structure of Proteins and the 2 Types of Structures
Some amino acids form hydrogen bonds whihc result in the Seconday Structures (Beta Pleated Sheet & Alpha Helix). The Beta Sheet can be either Antiparallel or Parallel
7 of 108
What is the Tertiary Structure?
Refers to the OVERALL folding of the polypeptide and its FINAL shape.
8 of 108
Whart causes the conformation of the Tertiary Structure to take place?
This conformation is caused by bonding such as interactions of the R Groups in hydrophobic regions, ionic bonds, hydrogen bonding, Van der Waals Interactions and Disulphide bridges
9 of 108
What is a Prosthetic Group?
It is a non-protein unit tightly bound to a protein necessary for its function.
10 of 108
What is the Quarternary Structure?
Quarternary Strucutre exists in proteins with several conneted polypeptide subunits.
11 of 108
Interactions between R Groups can be affected by what?
HIGHT TEMP- tertiary structure is destabalised= DENATURED & Changes in pH = No longer bond correctly and POLYPEPTIDE CHAIN UNFOLDS
12 of 108
Describe both Hydrophilic R-Groups and Hydrophobic R-Groups.
Hydrophillic R Groups will predominate at the surface of a solubl protein found in the cytoplasm and Hydrophobic R Groups may cluster at the centre to form a globular strucure.
13 of 108
What holds integral proteins within the fluid mosaic model of membrane structure?
Strong hydrophobic interactions.
14 of 108
Describe both Integral and Peripheral proteins with Examples.
Some Integral proteins are transmembrane, for example channels, transporters and many receptors. Peripheral proteins have fewer hydrophobic R groups interacting with the phospholipid bilayer.
15 of 108
What types of small non-polar molecules does the hydrophobic centre allow in?
Oxygen and Carbon Dioxide
16 of 108
What polar Molecules and Charged Ions does the hydrophobic centre act as a barrier to?
(Hydrogen, Sodium,)= Charged Ions, (Water, Glucose)=Polar Molecules
17 of 108
What is a Ligand?
A ligand is a substance that can bind to a protein.
18 of 108
Describe the shape of a ligand in reference to a protein.
The binding sites will have complementary shape and chemistry to ligand.
19 of 108
Describe DNA as a Ligand.
DNA binds to several proteins. Positively charged Histones bind to the negatively charged sugar-phosphate backbone of DNA in eukaryoes; the DNA wraps around histones to form NUCLEOSOMES packaging the DNA in chromoomes.
20 of 108
How does DNA control Transciption?
Some prote ins are transcription factors that bind to DNA to INNATE or INHIIBIT transcription.
21 of 108
Describe induced fit. (Ligand Binding & Conformational Change)
As a ligand/substrate binds to an enzyme's active site, the conformation of the protein changes. Induced fit occus when the correct substrate stars to bind resulting in a temporary change in shape of active site= increases binding & interaction with
22 of 108
What is an Allosteric Enzyme? (''Allo''=''Other'')
is an enzyme (& LIGAND) that can have its activity altered by a ligand called a modulator; they bind at secondary bining sites away from the active site.
23 of 108
Describe the Two Types of (Allosteric) Modulators.
Negative Modulators REDUCE the enzyme's AFFINITY for the substrate & Positive Modulators INCREASE the enzyme's AFFINITY for the substrate.
24 of 108
What is Cooperativity within Quarternary Structure?
Some proteins with Quarternary structrure show COOPERATIVITY in which changes in binding at one subunit alter the affinity of the remaining subunits.
25 of 108
Describe how Haemoglobin shows Cooperativity.
Haemoglobin is mad eup of 4 polupeptide subunits. Each contain a haem group capable of binding to a molecule of oxygen. When 1 of the subunitsbinds to O, the second binds easier & so on; the binding has INCRESEASED the AFFINITY for the next subunit.
26 of 108
How does Temperature and pH influence Cooperativity?
As TEMP INCREASES, AFFINITY FOR OXYGEN DECREASES & As pH DECREASES, AFFINITY FOR OXYGEN DECREASES
27 of 108
Describe the process of the reversal conformational change in proteins.
Desphorylation/Phosphorylation from particular R groups. This is a common form of Post-translational Modification. In this way, proteins such as enzymes & receptors can be regulated.
28 of 108
What is responsible for phorylation and dephosphorylation?
KINASE ENZYMES are responsible for phorphorylation & PHOSPHATE Enzymes catalyse dephosphorylation.
29 of 108
What do some proteins (ATPases) use for their phosphorylation?
ATP
30 of 108
Decribe Muscle Contraction and ATP.
Sacromeres contain proteins called Actin & Myosin. Myosin has heads that act as cross bridges as they bind to actin. When ATP binds to Myosin, the myosin head detaches from actin, swings forward &rebinds. This releases the ADP & a Phosphate= shortens
31 of 108
Decribe Muscle Contraction and ATP. p2
the sacromere and brings about muscle contraction
32 of 108
**Describe the role of Specific Transmembrane Proteins
They act as channels or transporters, control ion concentrations and concentration gradients.
33 of 108
Describe Channel Proteins, with an example.
Passage of molecules through channel proteins is PASSIVE, e.g. AQUAPORIN.
34 of 108
What are the 2 Types of Channel Proteins?
Ligand-gated channels are controlled by SIGNAL MOLECULES & Voltage-gated chanells are controlled by the changes in ion concentration.
35 of 108
Describe Transporter Proteins, with example/s.
They change CONFORMATION to transport molecules accorss a membrane e.g. NA/KATPase, Glucose Symport.
36 of 108
What are the two mechanisms in which the tansorter proteins work?
Facilitated Transport' a PASSIVE process where facilitated transport involves a conformational change in a protein e.g. Glucose Transport. Active Transport is used in the Sodium-Pottassium Pump.
37 of 108
What is a Signal Transduction?
Some cell surface receptor proteins convert extracellular chemical signals to a specific intracellular responce through a signal transduction pathway.
38 of 108
What may Signal Transduction pathway result in? (4)
The activation of an enzyme or G protein, a change in the uptake or secretion of molecules (upon the binding of insulin, glucose uptake increases), rearrangement of the cytoskeleton or activation of proteins that regulalate gene transcription.
39 of 108
Describe the role of G-proteins.
G proteins are involved in trasmitting signals from outide the cell inside. They can be ''Switched on''/activated by binding GTP and deactivated by binding GDP.
40 of 108
Describe the Sodium-Potassium Pump in great detail.
LOOK AT BLUE SHEET FOR ANSWER IN GREAT DEPTH
41 of 108
What are the functions for Na/KATPase? (4)
LOOK AT BLUE SHEET FOR ANSWERS
42 of 108
What is Nerve Transmission?
It is a wave of depolarisation of the resting potential of a neuron. This can be stimulated when an appropriate signal molecule triggers the opening of ligand-gated ion chanels at a synapse.
43 of 108
Describe the changes involved in Nerve Transmission.
LOOK AT BLUE SHEET FOR ANSWER IN GREAT DEPTH
44 of 108
** What are the 3 Domains of Life?
Archea, Bacteria & Eukaryota
45 of 108
What is the photoreceptor protein used by archea and where is it found?
Bacteriorhodopsin (found in Halobacteria)
46 of 108
What do bacteriorhodopsin molecules do?
They generate potential potential differences by absorbing light to pump protons accross the membrane.
47 of 108
Using the Blue Sheet, describe what happens when Bacteriorhodopsin generates ATP.
Archea converts light energy= chemical energy (ATP). When a photon of light is absorbed, the retinal undergoes a conformational change (STRAIGHT-> BENT); allowing protons to be pumped accross membrane and return through ATP Synthase= ATP
48 of 108
How do plants convert light energy to chemical energy?
Plants use a photosynthetic pigment called Chlorophyll. (found in Chloroplasts)
49 of 108
What membrane is found within the membrane-bound compartments (Grana) in Chloroplasts?
The Thylakoid Membrane
50 of 108
Describe ATP Synthesis is Plants. 1
When a molecule of chlorophyll absorbs light, one of its electrons is boosted up a higher energy level. The electron passes a no. of protein systems & as this happens, H ions are pumped accross the thylakoid membrane.
51 of 108
Describe ATP Synthesis is Plants. 2
The H ions are pumped accross the membrane and DIFFUSE the ATP Synthase= ATP
52 of 108
What forms the photoreceptors of the eye in Animals?
Retinal and Opsin and a CASCADE of proteins amplifies the signal.
53 of 108
Animals have what two types of photoreptor cells within the Retina of the eye?
Cone Cells (Wave-lengths) and Rod Cells (Low light)
54 of 108
Describe Rod Cells and Nerve Impulse.
In rod cells, the retinal-opsin complex is called Rhodopsin. When stimulated by a photon, a rhodopsin molecule activates G-protein molecules, actibating molecules of an ezyme. if the enzyme triggers sufficient product, a neve impulse might generate.
55 of 108
What are the 5 steps that converty light energy to a nerve impulse? 1
1. a photon of light excites rhodopsin 2. excited rhodopsin activated G-proteins 3. G-proteins excie enzyme molecules
56 of 108
What are the 5 steps that converty light energy to a nerve impulse? 2
4. The enzyme removes the Ligand from Na channels 5. The Na channels close so membrane potential increases, this hyperpolarisation stimulates a nerve impulse
57 of 108
What happens within Rod cells in low light intensities?
A very high degree of amplication from a single photon
58 of 108
What happens in cone cells when different forms of opsin combine with retinal to give phoreceptor proteins?
There is maximal sensitivity to specific wavelengths (green, blue, red & UV)
59 of 108
**What is Coordination?
Multicellular organisms achieve coordination of communication by means of EXTRACELLULAR signalling molecules, receptors and responces. In animals, communication is mediated by nervous transmission and hormonal secretion.
60 of 108
What are receptor molecules of target cells? (Coordination)
Are proteins with a binding site for a specific signal molecule.
61 of 108
Explain what happens during singnal reception. (Coordination)
Binding changes the conformation of the receptor and this can alter the responce of the cell.
62 of 108
What does specificity of signals mean? (Coordination)
Different cell types produce specific signals which can only be detected and responded to by cells with a specific receptor.
63 of 108
What happens in multicelular organisms? (Coordination)
Different cell types may show a tissue specific responce to the same signal.
64 of 108
Describe Hydrophobic Signals.
Hydophobic signals can pass through the membrane so their receptor molecules can be within the nucleus.
65 of 108
What can hydrophobic signals control?
Transcription
66 of 108
Give 2 examples of hydrophobic signals.
The thyroid hormone;Thyroxine and The steroid hormone
67 of 108
What happens in the absense of thryroxine?
Thyroxine receptor protein binds to DNA; Transcription of Na/KATPase gene is INHIBITED; less Na/KATPase is transcribed; Metabolic Rate REDUCES
68 of 108
What happens in the presence of thryroxine?
Thyroxine binds to thyroxine receotor protein; Receptor Protein undergoes a conformational change & can no longer bind to DNA; gene or Na/KATPase is transcribed; Metabolic Rate INCREASES
69 of 108
Describe steroid hormones acting as a transcription factor.
Steroid hormone passes membrane;Hormone binds toreceptor protein;The activated receptor protein acts as a transcription factor & binds to DNA; The activated receptor protein (transcription factor) brings about transcription of specific genes
70 of 108
Describe Hydrophillic Signals.
They require receptor molecules to be at the surfaace of the cell because they are not capable of passing the hydrophobic membrane.
71 of 108
What do Hydrophillic signals control?
Transduction
72 of 108
Give 2 examples of hydrophilic signals.
Peptide Hormones & Neurotransmitters
73 of 108
What do Transmembrane receptors do when a ligand binds to the cell?
Change conformation; the signal molecule does not enter the cell but the signal is TRANSDUCED accross the membrane of the cell.
74 of 108
What do transduced hydrophilic signals often involve?
Cascades of G-proteins or phosphorylationby Kinase Enzymes.
75 of 108
How does Glucose travel into the plasma membrane?
Transporter Proteins
76 of 108
Describe the process of The Hydrophillic Signalling Molecule; Insulin.
The binding of insulin to its receptor triggers recruitment of GLUT4 glucose transporter to the cell membrane of fat and muscle cells.
77 of 108
Explain the causes of both Type 1 & 2 Diabetes.
Type 1; caused by FAILURE TO PRODUCE INSULIN & Type 2; caused by loss of insulin receptor function (mainl caused by OBESITY)
78 of 108
How is both Type 1 & 2 Diabetes Treated?
Type 1; Regular Insulin injections & Type 2; Exercise and a goof healthy, balanced diet.
79 of 108
Describe the process of The Hydrophillic Signalling Molecule; Antidiruetic Hormone (ADH)
The binding of ADH to its receptor triggers recruitment of Aquaporin 2 (AQP2).
80 of 108
What does AQP2 provide?
A Highly Efficient Route for water to move accross membranes.
81 of 108
What does recruitment of AQP2 control?
Allows control of water balance in terrestrial vertebrates.
82 of 108
What is Diabetes Insipidus?
Failure to produce ADH or insensitvity of its receptor.
83 of 108
What does Inulin and ADH control?
Insulin; Involved in maintaining a constant blood glucose level & ADH; control the rate of water reabsorption in the nephron
84 of 108
**What is the importance of the cytoskeleton?
gives mechanical support & shape to cells.
85 of 108
What three types of proteins make up the cytoskeleton?
Intermediate Filaments, Microfilaments & MICROTUBULES
86 of 108
What are microtubules composed of?
They are composed of hollow straight rods made of globular proyeins called tubulins.
87 of 108
What do tubulins govern?
They govern the location and movement of membrane-bound organelles and other cell compartments.
88 of 108
Where are microtuules found and what do they form?
They are found in all eukaryotic cells and radiate from the centrosome & they form spindle fibres.
89 of 108
What does the cell cycle consist of?
Interphase and Mitotic Phase
90 of 108
What occurs during Interphase? (General)
During interphase, protein synthesis takes place, cystoplasmic organelles are synthesised, the cell grows and replicates its chromosome.
91 of 108
Describe each stage of Interphase.
G1; the initial growth period where proteins and organelles are synthesised, SPhase; cell continues to grow & copies its chromosomes in prep for mitosis &G2; anothher growth period where proteins and organelles are synthesised &then the Mitotic Phase
92 of 108
What 2 stages does the Mitotic Phase consit of?
Mitosis (when the nucleus and contents divide) and Cytokinesis (seperation of the cytoplasm into 2 daughter cells)
93 of 108
Describe the stages of Mitosis.
I Put My Arm There; Interphase, Prophase, Metaphase, Anaphase & Telophase; USE BLUE SHEET FOR DETAIL
94 of 108
What does an uncontrollable REDUCTION in the rate of the cell cycle result in?
Degenerative Disease (Alzheimer's & Parkinson's Disease)
95 of 108
What does an uncontrollable INCREASE in the rate of the cell cycle result in?
Tumour Formation
96 of 108
Where are checkpoints?
They are critical control points where stop and go ahead signals regulate the cell cycle
97 of 108
Where are the checkpoints within a cell cycle?
G1, G2 & Metaphase
98 of 108
When is the G0 Phase of use?
This when a go ahead signal at the G1 checkpoint is not reached, the cell may switch to a non-dividing state called the GO phase
99 of 108
Describe the 3 checkpoints of the cell cycle.
G1; (END) DNA replication must be completed & cell size, G2; (END) same thhing & M; (DURING METAPHSE) checks chromosomes are aligned on the metaphase plate properely
100 of 108
As the cell increases during G1, what happens?
Cyclin proteins accumulate and combine with regulatory proteins called cyclin-dependent kinases (Cdks) and activate them. Active Cdks cause the phospholylation or proteins that stimulate the cell cycle.
101 of 108
What happens if an insufficient threshold is reached? (Control of cell cycle)
The cell is held at checkpoint.
102 of 108
Describe the function of G1 Cdk?
The G1 Cdk phosphorylates a transcription factor, retinoblastoma (Rb) protein, allowing DNA replication in S phase.
103 of 108
What does DNA damage activation of? (3 things)
a protein called p53 which stimulate DNA repair, arrest the cell cycle or cause apoptosis (cell death).
104 of 108
What is apoptosis?
Apoptosis is programmed cell death
105 of 108
What is apoptosis triggered by?
Apoptosis is triggered by cell death signals which result in the activation of DNAases and proteinase (caspases) that destroy the cell.
106 of 108
Describe both cell death signals that originate extracellularly and intracellularly.
BLUE SHEET
107 of 108
Give 2 reasons as to why cell death must be controlled carefully in a multicellular organism
Denegerative disease; tumour growth
108 of 108

Other cards in this set

Card 2

Front

Why is the Proteome larger than the number of genes (genome)?

Back

This is due to Alternative RNA Splicing and Post Translational Modification

Card 3

Front

Describe the Structure of Proteins

Back

Preview of the front of card 3

Card 4

Front

What do Amino Acid Sequences do?

Back

Preview of the front of card 4

Card 5

Front

Name the 4 Different Types of Amino Acids

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Art & Design resources:

See all Art & Design resources »See all Everything resources »