Biology - Unit 1 Flashcards
1
Q
What are emulsions?
A
Insoluble liquid droplets suspended in another liquid
2
Q
What are suspensions?
A
Insoluble solid particles mixed with a liquid which needs to be stirred to stop it separating
3
Q
Why does water have a high surface tension?
A
Its molecules form hydrogen bonds between each other but no such bonds form between the water and the air
4
Q
What does amphoteric mean?
A
It can act as both an acid and a base
5
Q
What is the biological use of water being a solvent?
A
Allows the chemical reactions within cells to take place in the water in the cell
6
Q
What is the biological use of water having a high surface tension?
A
Used in plant transport systems
Life at the surface of ponds
7
Q
What is the biological use of water being amphoteric?
A
Acts as a buffer
8
Q
What are the main components of blood?
A
Plasma
Erythrocytes (Red blood cells)
Leucocytes (White blood cells)
Platelets
9
Q
What are the main features of plasma in the blood?
A
Main component of blood
Consists largely of water
Contains lots of dissolved substances
Contains fibrinogen for blood clotting
10
Q
What are the main features of red blood cells?
A
Biconcave High density Contain haemoglobin Formed in red bone marrow of long bones Live for 120 days No nucleus
11
Q
What are the main features of white blood cells?
A
Larger than erythrocytes Can change their shape Much lower density than red blood cells Contain nucleus Contain cytoplasm Formed in white bone marrow of short bones or in lymph glands and spleen
12
Q
What are the main features of platelets?
A
Fragments of megakaryocytes found in bone marrow
Involved in blood clotting
13
Q
What are the functions of blood plasma?
A
Transport digested food products Transport food molecules to cells Transport excretory products Transports hormones Maintain a steady body temperature Act as a pH buffer
14
Q
How do haemoglobin molecules release oxygen?
A
Oxygenated blood approaches tissues
Small decrease in partial pressure
Large decrease in % oxygen saturation
Oxygen released
15
Q
How is carbon dioxide transported to the lungs?
A
Diffuses into red blood cells
Combines with water -> carbonic acid (catalysed by carbonic anhydrase)
Dissociates to H+ and hydrogencarbonate ions (H2CO3)
Haemoglobin accepts H+ ion
Haemoglobonic acid formed
H2CO3 diffuses out and Cl- in
16
Q
What substances do the platelets release at a cut?
A
Serotonin - causes muscle contraction
Thromoplastin
17
Q
What are the events of blood clotting?
A
Platelets release thromboplastin
Thromboplastin catalyses prothrombin and Ca2+ into thrombin
Thrombin catalyses fibrinogen into fibrin
Fibrin forms a mesh of fibres trapping particles
Clot forms
18
Q
Where does the systemic circulation carry blood to and from?
A
Oxygenated from heart to cells
Deoxygenated back to the heart
19
Q
Where does the pulmonary circulation carry blood to and from?
A
Deoxygenated from heart to lungs
Oxygenated back to the heart
20
Q
What are the advantages of a double circulation system?
A
Separate oxygenated and deoxygenated blood
Different pressures
21
Q
Where do arteries carry blood?
A
From the heart to the cells
22
Q
What blood do arteries transport?
A
Most carry oxygenated
Pulmonary to lungs and umbilical from foetus to placenta carry deoxygenated
23
Q
What are the main features of arteries?
A
High pressure External layer of tough tissue Middle layer of elastic fibres and smooth muscle Smooth lining Small lumen when unstretched
24
Q
How does the structure of arteries change closer to the heart?
A
Larger lumen
More elastin fibres
Larger artery
25
What are the features of capillaries?
Link arterioles and venules
Thin walls for diffusion (one cell thick)
Large lumen
26
Where do the veins carry blood?
To the heart
27
What type of blood do the veins carry?
Most deoxygenated
| Pulmonary to heart and umbilical from placenta into foetus carry oxygenated
28
What two veins carry the blood into the heart?
Inferior vena cava from lower body
| Superior vena cava from upper body
29
What are the main feature of veins?
```
Relatively large lumen
Smooth inner surface
Thin layer of smooth muscle with few elastic fibres
Outer tough layer
Can hold a large volume of blood
Contain semilunar valves
```
30
What muscle does the heart contain?
Cardiac
31
What properties does cardiac muscle have?
Doesn't fatigue
| Myogenic
32
What does the inferior vena cava do?
Carries deoxygenated blood from the lower body to the right atrium
33
What does the superior vena cava do?
Carries deoxygenated blood from the upper body to the right atrium
34
What type of blood does the right heart carry?
Deoxygenated
35
What type of blood does the left heart carry?
Oxygenated
36
What does the right atrium do?
Receives blood from the great veins
Opens tricuspid valve
Fills right ventricle with blood
37
What are the main features of the tricuspid valve?
Made of three flaps
Known as atrioventricular valve
Prevents back-flow
Tendinous cords prevent turning inside out
38
What does the right ventricle do?
Fills with high pressure blood from atrium
| Pumps blood into pulmonary artery through semilunar valves
39
What are the main features of the pulmonary veins?
Returns blood from lungs to left atrium
| Low pressure
40
Which side of the heart is more muscles?
The right side
41
What artery does the left ventricle pump blood through?
The aorta
42
What are the three stages of the cardiac cycle?
Atrial systole
Ventricular systole
Diastole
43
What happens in diastole?
The heart is relaxed
Semilunar valves closed and AV open
Heart fills with blood
44
What happens in atrial systole?
Atria contracts
| Blood forced into ventricle
45
What happens in ventricular systole?
Ventricle contracts
| Blood pumped out of the heart
46
What is intrinsic rhytmicity?
Where the hearts cells contracts in a rhythm before the heart is formed
47
What controls the heart rate?
The cardiovascular centre
48
How does atherosclerosis form?
Endothelial cells damaged
Lipids build-up
Platelets form cap over fatty plague
49
Where is atherosclerosis more likely to form?
Arteries
50
What can cause atherosclerosis?
High blood pressure
| Smoking
51
What is an atheroma?
Fatty deposit
52
What does atherosclerosis cause?
Increased blood pressure (smaller artery)
Aneurysm (weakened artery wall)
Split blood vessels
Stroke
53
What are the two most common types of heart disease?
Angina and myocardial infarction
54
What causes angina?
Plague build-up in coronary arteries
Heart muscle gets less oxygen
Heart muscle anaerobically respires
Pain in the chest
55
How is angina treated?
```
Low-fat diet
Regular exercise
Losing weight
Not smoking
Drugs which cause dilation
Heart bypass surgery
```
56
What cause a heart attack (Myocardial infarction)?
Blocked coronary artery
57
What is a clot formed in a blood vessel called?
Thrombosis
58
What causes a stroke?
Interruption in blood supply to the brain
59
What are the symptoms of stroke?
```
Dizziness
Confusion
Slurred speech
Blurred vision
Numbness
```
60
What are the treatments for strokes?
Clot-busting drugs
61
What are the macronutrients we need in our diet?
Carbohydrates
Proteins
Fats/lipids
62
What are the micronutrients we need in our diet?
Mineral salts
| Vitamins
63
Why do we need carbohydrates?
Energy
| Broken down into glucose
64
Why do we need lipids in our diet?
Energy
| Excess stored as body fat
65
Why do we need protein in our diet?
Broken down into amino acids
| Some amino acids the body does not make
66
Why do we need mineral salts?
Calcium - skeleton/ teeth, contraction and clotting
| Sodium - nerves to work, contraction and heartbeat
67
Why do we need vitamin C?
Form connective tissue
| Prevent scurvy
68
What does scurvy cause?
Bleeding gums
Easy bruising
Painful joints
69
Why do we need fibre?
Holds water
| Provides bulk for the intestinal muscles
70
What are the main features of monosaccharides?
Sugars(CH2O)n
| Join in condensation reaction
71
What are the main features of disaccharides?
Form in condensation reaction
Glycosidic bond
(C6H10O5)n
72
What are the main features of sucrose?
Stored in plants like sugar beet/cane
Glucose + fructose
1,4 - glycosidic bond
73
What are the main features of lactose?
Found in milk
Glucose + galactose
1,4 - glycosidic bond
74
What are the main features of maltose?
Found in germinating seed like barley
Glucose + glucose
1,4 - glycosidic bond
75
What are the main features of amylose?
Only 1,4 - glycosidic bonds
Single chain
Forms a spiral
76
What are the main features of amylopectin?
1,4 - glycosidic bonds and 1,6 - glycosidic bonds
| Branched
77
What reaction breaks disaccharides?
Hydrolysis
78
What is starch made up of?
Amylose and amylopectin
| Can be store of energy or for sudden release
79
What are the main features of glycogen?
1,4 - glycosidic bonds and 1,6 - glycosidic bonds
Animal starch
Compact
Many side branches
80
What are the main features of lipids?
Good insulators
| Made of three fatty acids and a glycerol
81
What is glycerol?
Propan-1,2,3-triol
| All on same side
82
How do glycerol and a fatty acids combine?
Esterification/condensation reaction
Ester bond formed
If three fatty acids on - triglyceride
83
In what reaction do amino acids react together?
Condensation reactions
| Peptide bond
84
What is the formula of an amino acid?
NCC
NH2
H-C-R
COOH
85
What bonds are in proteins?
Peptide bonds
Hydrogen bonds
Sulphur bridges (R group)
Ionic bonds
86
What is the primary structure of a protein?
Linear sequence of amino acids in a peptide
87
What is the secondary structure of a protein?
The repeating pattern in the structure of the peptide chains
a-helix
B-pleated sheet
88
What is the tertiary structure of a protein?
The 3D folding of the secondary structure
89
What is the quaternary structure of a protein?
The 3D arrangement of more than one tertiary polypeptide
90
What are the main features of fibrous proteins?
Little or no tertiary structure
Long, parallel polypeptide chains with occasional cross-linkages forming fibres
Insoluble in water
Tough
91
What are the main features of globular proteins?
Complex tertiary and maybe quaternary structures
Folded into spherical shapes
Form a colloid
92
What are the main features of a conjugated protein?
Joined to prosthetic group
| Haemoglobin
93
What are lipoproteins?
Proteins conjugated with lipids
| Low-density (LDL) or HDL
94
What is the basal metabolic rate?
Minimum energy needed to live
95
How is BMI calculated?
Weight (kg) / height^2 (m^2)
96
What is risk?
The probability that a particular event will happen
97
What is valid?
Properly designed to answer the questions being asked
98
What is reliable?
Repeatable
99
What factors can affect risk of CVD?
```
Smoking
Weight
Exercise
Stress
Diet - want less LDL and more HDL
```
100
What are drugs that reduce blood pressure?
Antihypertensives
101
What are some antihypertensives and how do they work?
Diuretics - Urinate - remove excess so less blood
Beta blockers - slow heart rate
Sympathetic nerve inhibitors - prevent rise in blood pressure
ACE inhibitors - prevent angiotensin from being produced - no constriction
102
How do statins work?
Lower cholesterol levels
Improve LDL and HDL balance
Reduce inflammation
103
What are side effects of statins?
Very small chance of fatal muscle inflammation
| Small chance of liver failure
104
What are plant stanols (sterols)?
Similar to cholesterol
| Reduce amount of cholesterol absorbed
105
What are some anticoagulants and what do they do?
Warfarin - Interferes with prothrombin production
| Platelet inhibitor drugs- make platelets less sticky
106
What are colloids?
Solutions with larger solute particles than solvent particles
107
What are the two types of nitrogen- containing bases?
Purine - two rings. A and G
| Pyrimidines - one nitrogen-containing ring. C, T and U
108
What is the phosphate group made of?
(PO4)^3-
109
What holds together the two strands in DNA?
Hydrogen bonds between complementary base pairs
110
What is the process of DNA replication?
DNA helicase splits strands
Free nucleotides form hydrogen bonds
DNA polymerase and DNA ligase join nucleotides together
111
What is the type of replication involved in DNA replication?
Semi conservative
112
How was it discovered that the method of DNA replication is semi conservative?
Grew e. Coli in medium with only 15N
Transferred to medium with only normal 14N
All DNA same density so semiconservative
113
What are nucleotides made of?
Phosphate
Pentose sugar
Organic nitrogenous base
114
Where does transcription occur?
In the nucleus
115
Where does translation occur?
On the surface of ribosomes
116
Which strand of DNA acts as a template for mRNA?
The antisense strand
117
What is the method of translation?
```
mRNA engulfed by ribosome
tRNA attaches to specific amino acids
tRNA molecule lines up against matching mRNA on ribosome
Peptide links formed between amino acids
tRNAs unbind to pick up more amino acids
```
118
What is a mutation?
A change in the genetic code
119
What are point mutations?
One or a small number of nucleotides miscopied
120
What are chromosomal mutations?
Changes in gene position within the chromosomes
121
What are gene deletion mutations?
Where a gene or set of genes are not copied
122
What is duplication mutation?
Where a gene or set of genes are copied multiple times
123
What are inversion mutations?
Where genes switch positions
124
What is s translocation mutation?
Where genes are copied onto the wrong chromosome
125
What are whole-chromosome mutations?
Where an entire chromosome is lost during meiosis or duplicated in one cell by errors in the process
126
What are anabolic reactions?
Reactions that build up new chemicals
127
What are catabolic reactions?
Reactions that break substances down
128
What is enzyme specificity?
Only catalyse specific reactions
129
What names do enzymes have?
Recommended name - urease
Systematic name
Classification number
130
What is the induced-fit hypothesis?
Active site not fully complementary to substrate until substrate fits into it
131
What is an enzymes molecular activity (turnover number)?
The number of substrate molecules transformed per minute by a single enzyme molecule
132
What is the temperature coefficient of an enzyme?
Rate of reaction at x+10C / rate of reaction at xC
133
What is a genes locus?
Its position on a chromosome
134
What is polygenic?
Controlled by several interacting genes
135
What is Thalassaemia?
```
Genetic disorder
Affect haemoglobin polypeptide chains
Prevents formation of either a or B chains in haemoglobin
Symptoms of anaemia
No cure
Treated by blood infusion
```
136
What is alpha Thalassaemia?
Polygenic inheritance
Commonly caused by gene deletion
Various severities
Milder increases malaria resistance
137
What is beta Thalassaemia?
Mutations on one gene
Various severities
Most severe: Cooley's anaemia
Recessive allele
138
What is albinism?
Melanin pigment does not form
Polygenic mutations
E.g. Tyrosinase not formed so no melanin produced
Recessive allele
139
What are multifactorial diseases?
Cause by combination of genes and lifestyle
140
What is the cell membrane structure?
```
Phospholipid bilayer (fatty acid tails away from solution)
Membrane proteins
Fluid mosaic model
```
141
What is facilitated diffusion?
Diffusion across a membrane through a protein
142
What is an isotonic solution?
Same osmotic concentration inside and outside
143
What is a hypotonic solution?
Osmotic concentration of solution lower than that of the cells
144
What is Fick's law?
Rate of diffusion= (surface area * concentration)/exchange membrane thickness
145
What is the structure of an alveoli?
Folded sac - high surface area
Lung surfactant - prevents collapse
Thin walls
Steep concentration gradient
146
What is the method of keeping mucus runny?
Chloride ions pumped into epithelial cells from surrounding tissue fluid
Chloride ions diffuse into fluid in airways through chloride channels(CFTR channels)
CFTR channel proteins prevent sodium ion exit from airways
Water moves out of cells and mixes with mucus
147
What does cystic fibrosis cause?
The CFTR channel to not work
| Thick, sticky mucus
148
What are symptoms of cystic fibrosis?
Severe coughing fits - mucus build-up in lungs
Breathless
Pathogen build-up in lungs
Prevents digestive enzyme movement to gut - improper digestion and stay in pancreas (damage to pancreas)
More difficult for digested food to be absorbed into blood
Blocked cervix/tube carrying sperm out
Salty sweat
149
What are treatments of cystic fibrosis?
```
Physiotherapy
Balanced diet
Enzymes taken with food
Drug therapies
Transplant
Infertility treatments
Gene therapy
```
150
How does gene therapy work?
Restriction endonuclease cuts out gene and cuts plasmid
DNA ligase joins plasmid and gene
Recombinant DNA produced
Vector inserted
151
What are problems with gene therapy?
Extracellular barriers
Intercellular barriers
Keeping the gene expression going
152
What are methods of genetic screening?
Amniocentesis
Chorionic villus sampling
Preimplantation genetic diagnosis
153
How does amniocentesis work?
16th week of pregnancy
Amniotic fluid removed
Cells cultured
154
What are the disadvantages of amniocentesis?
Late in pregnancy
2-3 weeks before results
1% risk of spontaneous abortion
155
How does chorionic villus sampling work?
8-10 weeks of pregnancy
| Embryonic tissue taken
156
What are the disadvantages of chorionic villus sampling?
2.5-4.8% risk of spontaneous abortion
| Can't detect problems in paternal X chromosomes
157
How does preimplantation genetic diagnosis work?
Egg and cell fertilised outside body
Secondary oocyte removed from each embryo
Genetic makeup checked and best implanted
