Learn bio Flashcards
1
Q
What happens at primary level?
A
- Peptide bonds are formed.
- sequence of amino acids are formed.
2
Q
What is at the secondary structure?
A
- Hydrogen bonds formed
- Initial folding of polypeptide chain.
3
Q
What is In the tertiary structure?
A
- Overall 3D shape.
- Ioinic bonds are formed.
4
Q
Formation of hydrogen bonds between two molecules of water?
A
- Between O and H at adjacent molecules.
- Between electropositive and electronegative.
- Water molecule is polar.
5
Q
Why is waters ability to act as a solvent important?
A
- Supports metabolic reactions.
- Allows ions to separate.
- Allows organism to absorb minerals.
6
Q
Structure of amino acids molecule,
A
- Look in revision guide and practice
7
Q
Structure of collagen
A
- Peptide bonds between amino acids.
- Every 3rd Amino Acid is glycine.
- Three polypeptide chains.
- Hydrogen bonds between polypeptide chains.
8
Q
Structure of Haemoglobin
A
- Hb is globular.
- Hydrophobic group on inside and hydrophilic on outside.
- 4 polypeptide chains, 2 beta and 2 alpha.
9
Q
Which bases bind to which bases?
A
- A-T
- C-G
10
Q
What are the two factors which can causes variation?
A
- Genetic.
- Environment
11
Q
What are the use of remaining combinations?
A
- Some are used as stop codons.
- Several triplets code for one amino acid
12
Q
Describe the process of translation
A
- mRNA moves to ribosomes.
- tRNA molecule binds to mRNA.
- Anticodons bind to codons.
- Specific amino acids bind to codons.
- Peptide bonds between Amino Acids are formed.
13
Q
Structural Differences between RNA and DNA
A
- Uracil instead of thymine.
- RNA only had one strand, DNA had 2.
- RNA is shorter
14
Q
Why is complementary base pairing important?
A
- DNA can be replicated without error.
- Allows hydrogen bonds to form.
15
Q
Why is the glucose molecule suited to its function?
A
- Insoluble, can be transported easily.
- Easily broken down, to produced ATP.
16
Q
Structural similarities between deoxyribose and other components of DNA molecule.
A
- Part of the nucleotide.
- Attached to phosphate.
17
Q
Name the bond formed between two amino acids as how is it formed?
A
- Peptdie bond.
- Condensation reaction between carboxyl group and amine group.
18
Q
Where are hydrogen bonds found in biological molecules
A
- In protein secondary structure.
- Between polypeptide chains in tertiary structure.
- Between chains of cellulose.
- Between strand of DNA.
19
Q
Roles of cholesterol in living organism
A
- Regulates fluidity In phospholipids bilayer.
- Makes the skin waterproof.
20
Q
How is the molecular structure of cholesterol similar to carbohydrate?
A
- Both contains C,H and O.
21
Q
Why is glycogen a good storage molecule?
A
- It is compact.
- Lots of branches for enzymes to attach to.
- Can be broken down easily.
22
Q
Similarities between DNA and RNA
A
- Both have a sugar-phosphate backbone.
- Both have four different nitrogenous bases.
- Both contain a pentose sugar.
23
Q
Differences between DNA and RNA
A
- DNA contains thymine and RNA uracil.
- DNA has double stranded, RNA is single stranded.
- DNA only found in nucleus. RNA found in Nucleus and cytoplasm
24
Q
Why is mRNA molecule shorter than a DNA molecule?
A
- mRNA only copies one section of DNA.
- DNA compromises many genes.
25
How does high temperature disrupt a tertiary structure protein?
- High kinetic energy.
- Protein molecule vibrates.
- Ionic bonds break.
- Change in 3D shale.
26
How to test for lipids
- Ethanol and water.
| - Present=white emulsion.
27
How to test for reducing sugar
- Benedicts solution.
| - Present=Brick-red precipitate.
28
How to test for protein
- Biuret I and II
| - present=Lilac colour.
29
Water molecule structure
- Hydrogens are delta positive.
- Oxygens are delta Negative.
- Hydrogen bonds between water molecules.
30
How does a Amino Acid bond on?
- Peptide bonds forms.
- Between Amine group and Carboxyl group.
- Condensation reaction.
31
How to R groups interact to determine the tertiary structure?
- Some E groups attract/repel.
- Disulfide bonds between cysteine atoms.
- Ionic bonds between oppositely charged R groups.
32
Structural differences between glycogen and collagen.
- Glycogen= Branched. Collagen=Linear.
- Glycogen=Non helical. Collagen=Helical.
- Glycogen= Glycosidic bonds. Collagen=Peptide bonds.
33
Which sugar is the final products of the digestion process?
- Beta glucose.
34
Why are different enzymes involved in each stage of the digestion process?
- Enzymes are specific.
- Substrates are different shapes.
- Active site and substrates need to be complementary.
35
Explain the term biological catalyst
Speeds up metabolic reactions
36
What is the colour of iodine solution in the presence of starch?
- Black
37
How are hydrogen bonds formed?
- Between oxygen and hydrogen atoms.
| - Between electronegative and electropositive molecules.
38
Effect of high temperature on the structure of the membrane
- Phospholipids have more KE.
- Larger gaps between phospholipids occur.
- Causes phospholipids to melt.
- Proteins denature.
39
Functions of membrane within cells.
- Form vesicles.
- Provides surface area for attachment of enzymes/ribosomes.
- Seperates contents of Organelle and cytoplasm.
40
How does the plasma membrane contribute to cell signalling?
- Release of molecule by exocytosis.
- Glycoproteins acts as receptor.
- Receptors are specific.
- Shape of receptor and signal are complementary.
- Attachment of signal molecule causes change.
41
How are vesicles move between organelles.
- Cytoskeleton.
- Move along Microtubules.
- Uses ATP
42
Examples of active transport
- Ions into root hair cells.
| - hydrogen ions out of companion cells.
43
Outline the process of budding in yeast
- Nucleus divides.
- Organelles move into bulge.
- bulge pinches off.
44
Functions of glycoproteins in the cell surface membrane
- Act as antigens.
- Act as cell receptors.
- Cell recognition.
- Cell adhesion.
- Allows communication across membrane.
45
Types of cells in the phloem tissue
- Companion cell.
| - Sieve tube element.
46
Independent Assortment of homologous chromosomes.
- Occurs in metaphase 1 and 2.
| - So homologous pairs have different alleles.
47
Crossing over
- Occurs in prophase 1.
- Chromatids will have new combinations of alleles p.
- Produces large number of allele combinations.
48
Why are new branches seen growing from a position just under the bark of the cut surface?
- This is where cambium is found.
- Mitosis occurs in cambium.
- New cell specialised.
49
Locations where growth occurs in plants.
- Cambium.
| - Meristem.
50
Why does meiosis need to have twice as many stages as mitosis?
- To halve the number of chromosomes.
| - To separate homologous pairs.
51
What feature of DNA is changed as a result of mutation?
- Sequence of nucleotides.
52
Effects mutation can have on the structure and function of proteins
- Different primary Structure.
- Can be shorter due to deletion or stop codon.
- Can be longer due to insertion.
- Could be unchanged due to silent mutation.
- Function could be worse.
53
Why must genetic material replicate before mitosis?
- So cells are genetically identical.
| - So both cells receive a full copy of DNA
54
What is a homologous pair of chromosomes?
- A pair of chromosomes which have the same genes.
- They are the same length.
- One maternal and one paternal.
- Attach to each other during meiosis
55
Where can meristematic tissue found?
- Apex of root.
| - Apex of shoot.
56
How are products of meiosis different to the products of mitosis?
- Cells produced aren’t genetically identical in meiosis.
57
How is cell division in plants different to cell division in animals?
- Cell wall forms between new cells in plants.
- Only occurs in meristem for plants.
- No centriole in plants
58
Where in plants does cell division occur?
- Meristem
59
Why are lungs considered to be an organ?
- They are a group of tissues that work together.
| - To carry out gas exchange.
60
Adaptations of a guard cell
- A vacuole, To take up water.
| - Mitochondria, to generate ATP.
61
How o alveoli create a surface for efficient gas exchange?
- Wall is once cell thick, provide short diffusion pathway.
- Squamous cells provide a short diffusion pathway.
- Elastic fibres recoil, maintains conc. gradient.
- Large number of alveoli provided large SA.
- High SA:V ratio.
62
Why do large multicellular organisms needs a transport system?
- Low SA:V ratio.
- High metabolic rate.
- Diffusion distance is too great.
- To prevent build up of CO2.
63
ECG full name
- Electrocardiagram.
64
Why is there a delay between the excitation of the atria and ventricles?
- Allow time for atria to contract properly.
- Allow time for ventricles to fill.
- So ventricles do not contract too early.
65
Why is the excitation wave carried to the apex?
- So contraction starts at the bottom.
- To push blood upwards.
- Complete emptying of ventricles.
66
What is tidal volume?
- The volume of air taken in.
| - During a normal breath.
67
Explain the process of exhalation
- External intercostal muscles relax.
- Rib cage makes upward and outwards.
- Volume of thorax decreases.
- Pressure in thorax increases.
- Air leaves down pressure gradient.
68
Causes of smokers cough and effects.
- Damages cilia.
- Build up of mucus in airway.
- more pathogens accumulate.
- cough is to increase airflow by removing mucus.
- Lumen of airways narrows.
- Flow of air restricted.
- Formatoj of scar tissue
69
Role of elastic fibres during ventilation
- Prevent bursting.
| - They recoil to Help expel air and to return air sac to its original shape.
70
How do different cells and tissues enable effective gaseous exchange?
- Elatic fibres expels air.
- Squamous epithelium provides a short diffusion distance.
- Cartilage holds open the airway.
- Red blood cells help maintain a steep concentration gradient.
71
How to use a spirometer to measure tidal volume?
- Breath not through nose.
- Person breaths normally.
- Measure height if waves on the trace.
72
How do you use a spirometer to measure oxygen uptake?
- Measure the volume of o2 used.
- Measure the time taken.
- Divide volume by time taken.
73
What happens to the air chamber during inspiration?
- The aid chamber falls
74
Precautions that should be made when using a spirometer
- Wash the mouthpiece.
| - Check the background health of the volunteer.
75
Why should a person using a spirometer to measure vital capacity wear a nose clip?
- to ensure all air breathed out comes from the chamber.
| - To prevent entry of air through nose.
76
How do the goblet cell and the Ciliated epithelial cell work together to clear dust off the lung surface?
- Goblet cells release mucus.
- Mucus traps dust particles.
- Ciliated cell wafts mucus.
- To back of the mouth.
77
Function of smooth muscle fibres
- Control flow of air.
78
Why are capillaries and alveoli close together?
- To maintain a steep concentration gradient.
| - So the diffusion distance is not too far.
79
How can the structure of bronchioles become reduced in diameter?
- Contraction of smooth muscles.
| - Extra mucus production.
80
Why is it difficult to expel air from the lungs if the bronchioles have become reduced in diameter?
- Reduced diameter means increased friction.
81
How are hydrogencarbonate ions produced in the erythrocytes?
- Co2 diffuses into erythrocytes.
- Co2 reacts with water.
- Catalyses by carbonic anhydrase.
- Forms carbonic acid.
- Carbonic acid dissociates to form hydrogencarbonate ions and proteins.
82
Explain the Bohr effect
- Co2 Reduces the affinity of Hb for oxygen.
| - Prevents fall of PH in cells.
83
Health definition
- The physical and mental well-being of a person.
| - Absence of disease
84
How do components of tobacco affect the cardiovascular system?
Nicotine:
- Increases stickiness of platelets.
- Formation of blood clot.
- Causes release of adrenaline.
- Causes constriction of arterioles.
- Reduced blood flow.
85
Why is fetal Hb to the left of Adukt Hb on a graph?
- Placenta had low po2.
- Adult Hb will dissociate in low po2.
- Fetal Hb has a higher affinity for oxygen.
- Fetal Hb is able to take up more oxygen in placenta.
86
How do substances such as glucose and oxygen enter the tissue fluid from capillaries?
- Diffusion.
- From high concentration to low concentration.
- Hydrostatic pressure in capillary is greater than in tissue fluid.
- Capillary walls are leaky.
- Fluid forced out of capillary, small molecules leave with fluid.
87
Why is lignin essential in the wall of a xylem vessel?
- Provides strength to xylem vessel.
- prevents collapse of vessel.
- Because transpiration can cause tension.
88
Why is cartilage essential in the trachea?
- Supports trachea.
- During inspiration.
- Allows volume of thorax to increase.
89
What is the mammalian blood circulatory system?
- double closed
90
What cuases fluctuations of blood pressure?
- Contraction increases predsure.
| - Relaxation decreases lressjre
91
What is in arterial blood?
- High hydrostaic pressure.
- Large proteins.
- neutrophills.
- Erythrocytes.
92
What is/isnt in tissue fluid?
- Low hydrostatic pressure.
- No large proteins.
- Neutrophils.
- No Erythrocytes.
93
What is/isnt in lymph?
- Low hydrostatic pressure.
- No large proteins.
- Neutrophills.
- No erythrocytes.
94
Advantages of a closed circulatory sytem
- Maintain high blood pressure.
| - Increase rate of flow.
95
How is the artery wall adapted to withstand pressure?
- Wall is thick.
| - Thick layer of collagen which provides strength.
96
How is an artery wall adapted to maintain pressure.
- Thick layer of elastic tissue.
| - Contricts lumen.
97
Why is the wall of the left ventricle thicker than the wall of the left atrium?
- So it can create more force.
- Needs to create higher pressure.
- Has to push blood against greater resistance.
- Left ventricle pumps blood further.
98
Benefits of the Bohr shift to acitvely respiring tissues.
- Respiring tissues need more O2.
- For aerobic respiration.
- Respiring tissues produce more C02.
99
Describe the role of the SAN and the AVN in coordinating the cardiac cycle
- SAN initiated heartbeat.
- SAN sends electrical impulse over atrial walls.
- AVN delayed impulse, so atrium can contract fully.
- AVN sends impulse down septum.
100
How is the wall of an artery differnet to the wall of a vein?
- Artery has no valves, veins do.
| - Arteries have more collagen than veins.
101
How is hydrostatic pressure generated in the heart?
- Contraction of ventricle wall.
102
Why does pressure of the blood decrease as blood moves away from the heart?
- More vessels.
- Vessels have larger lumen.
- Reduced resistance to blood flow.
103
What is the type of muscle found in heart chambers?
- Cardiac
| .
104
What does a closed ciculatory system mean?
- Blood is maintained inside the vessels.
105
What is a single cirulatory system?
- Blood passes throug the heart once for every cirulation of the body.
106
How is the action of thr heart initiated and coordinated?
- SAN initiates excitation.
- Wave of excitation spreads over atrial walls.
- AVN recieves wave of excitation.
- Atria contracts.
- Delay at AVN to allow atria to fully contract.
- Excitation spreads down septum.
107
Why is the excitation wave carried to the apex?
- So ventricular contraction starts at the bottom.
- To push blood upwards.
- Complete emptying of ventricles.
108
How are guard cells adapted to their role?
- Unevenly thickened wall.
- Chlorplast to provide ATP.
- Able to bend.
109
Explain the cohesion-tension theory
- Evaporation at the top of the plant.
- Creates tension in the xylem.
- Water molecules stick together.
- Chain pulled up by tension.
110
How are companion cells adapted?
- Lots of mitochondria to provide ATP.
| - Plasmodesmata between companion cells.
111
Difference between transpiration and transpiration steam.
- Transpiration- Loss of water vapour from the stomata.
| - Transpiration stream- Movement of water from the roots to the leaves.
112
Why is transpiration unavoidable during the day?
- Stomata are open.
- due to high temparature.
- Water vapours leaves.
113
Adaptations of sieve tubes.
- Few organeless.
- Litlle cytoplasm.
- Elements join end to end.
114
Xylem adaptations
- No end walls.
- Lignified walls.
- No organelles.
115
How does transpiration contriubute to the mechanism of water transport up the stem?
- Water loss is replaced.
- Via apoplast pathway.
- Down water potential gradient.
- Lost water is replaced by water from xylem.
116
Why does the potometer only give estimates of the rate of transpiration?
- Potometer measured water uptake.
- Not all water taken up is lost.
- Some is used in photosynthesis.
117
Why is water loss from the leaves of a plant unavoidable?
- Stomata opens to allow gas exchange.
| - For photosynthsis.
118
What is meant by the terms source and sink?
- Source- Site where sucrose are loaded into phloem.
| - Sink- Site where sucrose are removed from the phloem.
119
Explain the function of pits
- Allows water to move in and out of the cell between vessels.
120
Define the term parasite
- Lives on a host.
- Feeds off a host.
- At the expense of the host.
121
Why don’t primary defences work against vectors?
- Vectors feeds on blood.
| - Skin cannot act as a barrier.
122
How does the strucute of antibodie allow them to perform their function?
- 4 polypeptide chains, 2 light and 2 heavy.
- Variable region which allows bidning to antigen.
- Two variable regions allow binding of more than 1 antigen.
- Constant region allows binding with phagocytes.
- Hinge region allows flexibility.
123
What is neutralisation?
- Covers receptor site.
| - Prevent binding of toxins.
124
What is agglutanation?
- Pathogens clump together.
| - Clump is too large to enter host cell.
125
What does bacteria become ‘immune’ to antibiotics?
- Immunity involves an immuse system, which bacteria do not have.
126
Why are phagocytes described as secondary defence against pathogens?
- They are involved after pathogen has entered the body.
127
Why is the response involving phagocytes non-specific?
- Phagoyctes are able to engulf many different of pathogens.
128
How is a pathfoen destroyed by a phagocyte?
- Pathogen is engulfed. (Phagocytosis).
- This forms a phagosomes.
- Phagolysosomes fuse with eachother.
- Enzymes in lysosomes break down the pathogen.
- Into Amino Acid.
129
How is bacteria transmitted?
- Through droplets contraining pathogens.
| - Released by sneezing.
130
How do mosquitos transmir the malarial parasite to a human?
- Mosquito is a vector.
- Parasite present in mosquito saliva.
- Infected mosquito feeds on human.
- Parasite passes into blood.
131
Similarities between B and T lymphocytes.
- Both form part of the immune system.
| - Both undergo clonal expansion.
132
Differences between B and T lymphocytes
- T lyphocytes are matured in thymus, B lymphocytes matured in the bone marrow.
- T lymphocye secrete substances which kill infected cells, B lymphocytee manafacture antibodies.
- T lymphocytes activate other lymphocytesm B lymphocytes do not.
133
Difference between primary and secondary immune respones
- Secondary immune responses prodcuce more antibodies.
134
Memory cells function
- Recognise pathogens.
- Produce a clone.
- Make antibodies.
135
Name two primary defences and explain how they prevent entrynof pathogens into the body
- Skin- Acts as a physcial barrier to prevent entrt of microorganisms.
- Mucus- Traps pathogens
136
Name the type of cell that produces antibodies
- Plasma cells.
137
What type of immunitt is provided by antibodies in breastmilk
- Natrual Passive.
138
Aims for thr convention of internarion trade in endangered species
- To regulate trade of speices.
| - To ensure that trade does not endanger wild populations.
139
Aims of Rio Convention On Biological Diversity
- Sustainable use of habitats.
| - Share genetic resources.
140
What is taken into account when describing the biodiversity of an area?
- Species richness.
- Species Eveness.
- Number of habitats.
141
Why is a reduction in biodiverity problematic for agriculuture in the future?
- Loss of genetic diversity.
- Agricultrual requirements may change in the future.
- Lost genes may have been useful.
142
Advantages of using a seed bank as opposed to adult plants
- Are able to store more.
- Less susceptible to disease.
- Cheaper to transport.
143
Importance of sampling
- Difficult to count every specie.
| - Sample provides an estimate.
144
Why is important to take samples in fence and unfenced areas?
- To see the effect of the specie.
145
Significance of a low value of simpons index of diversity
- Habitat dominated by one species.
| - Habitat is less likely to cope with change.
146
How is phylogeny related to classification
- Phylogeny is the evolutionary histort of organisms.
| - Phylogeny can allow scientists to classify species as the saem because of their physical features.
147
Is the ‘Genus’ the first of the second word?
First
148
Outline the proccess used to measure the biodiversity of plant species in grassland.
- Use a quadrat.
- Random sampling.
- Count number of organisms in the quadrat.
- Repeat process.
- Calculate mean.
149
Factore thr EIA consider.
- Size of development.
- Which habitats are present in the area.
- Potential damage to organisms.
150
What does the Rio convention of biological diversity do? (CBD)
- Develops international stratergies on thr conservation of biodiversity.
- Plans how ronuse animal and plant resources in a sustainable way.
- Provides guidance to government on how to conserve biodiversity.
- Made it a law that conserving biodiversity is everyones responsibility.
151
What does the convention of international trade in endangered species (CITES) do?
- Regulates trade of wild animals.
- Members agreed to make ir illegal to kill endangered speices. (Protect endangered species).
- Limit trade through licencing .
- Raise awarness of threats to biodiversity.
152
What does The Countryside Stewardship Scheme (CSS) do?
- Promote specific management techniques.
- Government would pay landowners who followed the management techniques.
- As a result, species have begun to rebuild in numbers.
153
Hat can be done to esnure sucdsd of breeding programmes?
- Check animals health.
- Provide food for animal.
- Raise public awareness.
154
Explain the importance of species evenness in determining biodiversity in a habitat.
- Species evenness= Number of individuals in each species.
- Higher species evenness= High biodiversity.
- Species eveness is used to calculate simpsons index.
155
Implications of a high value of simprons index of diversity on planning.
- Habitat has High biodiversity.
| - So should not be modified
156
Now to do selective breeding?
- Select best offspring.
- Breed offspring with best offspring.
- For mant generatons.
- Avoid breeding closelt related individuals.
157
Where is the core body tempersture is detected?
- Hypothalamus.
158
What is meant by the term hoemostasis?
- Maintainign a stable internal enviroment.
| - Around a set point.
159
How is negative feedback used to cotrol an increase in blood glucose conc.?
- Receptor detects increases in blood glucose conc.
- Beta cells release insulin.
- Increased absorption of glucose by effector cells.
- Glucose is converted unto glycogen. (Glycogenisis).
- Increased use of glucose in ATP production.
160
How is negative feedback used to cotrol a decrease in blood glucose conc.?
- Receptor detects the decrease in blood glucose conc.
- Alpha cells release glucagon.
- Increased conversion of glycogen to glucose. (Glycogensisis).
- Glucose leaves cells into blood by facilitated diffusion.
161
How is type 1 diabeties treated.
- Daily hormone injects of insulin.
| - To control blood sugar concentration.
162
How it type 1 diabeties caused
- Diet with high amounts of refined carbohydrates including sugars such as glucose.
- Very little exercise.
163
Describe and explain the role of ATP in the cell.
- Releases 30 KJ or energy.
- When a phosphate group is removed.
- By hydrolysis.
164
Which process is carried out by cristae?
- Oxidative phosphorylation.
165
Which part of thr adrenal gland releases aldosterone?
- Cortex
166
Explain the role od the loop of henle in the production of urine
- Loops of Henle causes a decrease in water potential in medulla.
- In acending limb, there is active transport outward of ions.
- Descening limb is permeable to water.
- Water potential of medulla is lower than the filtrate.
- Water is removed from the filtrate.
167
What happens at the Bowmans capsule/Glomerulus?
- Ultrafiltration.
