Paper 1 Flashcards
1
Q
Mass flow hypothesis:
A
-In source, sugar actively transported into phloem
- by companion cells
- lowers water potential of sieve cell and water enters by osmosis
2
Q
Cohesion-tension theory:
A
- evaporation of water from leaf cells
- lowers water potential of leaf cells
- water pulled up xylem creating pressure
- water molecules cohere by hydrogen bonds
- forming water column
3
Q
Nucleus structure and function:
A
- Nuclear envelope and pores
- double membrane
- Nucleoli
- Stores genetic information for polypeptide production
- DNA replication
4
Q
Rate of transpiration increases during the day because:
A
- Rate of transpiration increases due to increased temp.
- increased water diffusion gradient
- stomata are open to allow gas exchange
5
Q
Transport of carbohydrates in plants:
A
- Sucrose actively transported into phloem
- by companion cells
- lowers water potential and water enters by osmosis
- produces higher hydrostatic pressure
- removed from phloem by active transport
6
Q
Induced fit:
A
- Substrate binds to active site
- active site changes shape slightly so complementary to substrate
7
Q
Role of micelles:
A
- Carries fatty acids to lining
- maintains higher conc. of fatty acids to lining
- fatty acids absorbed by diffusion
8
Q
How an enzyme is phosphorylated:
A
- attachment of phosphate
- From hydrolysis of ATP
9
Q
Formation of ES complex increases rate of reaction:
A
-Reduces activation energy
-Due to bending bonds
10
Q
General structure of an amino acid:
A
R
H2N - C - COOH
H
11
Q
Degenerate code means:
A
- More than one codon codes for a single amino acid
12
Q
Vaccination programme and humoral response:
A
- B cells specific to the venom divide by mitosis
- Produce plasma cells and memory cells
- Second dose produces antibodies in higher conc. and quickly
13
Q
Role of DNA helicase and polymerase:
A
- DNA helicase causes breaking of hydrogen bonds
- DNA polymerase joins nucleotides
- Forming phosphodiester bonds
14
Q
Gross structure of human gas exchange and how we breathe:
A
- Trachea, bronchi, bronchioles and alveoli
- Breathing in: Diaphragm contracts and external intercostal muscles contract
Volume increases and pressure decreases in thoracic cavity - Breathing out: Diaphragm relaxes and internal intercostal muscles contract
Volume decrease and pressure increases in thoracic cavity
15
Q
Structure and property of triglycerides and phospholipids:
A
- Contains glycerol
- Fatty acids can be saturated or unsaturated
- Insoluble in water
- Triglycerides have three fatty acid and phospholipids have two fatty acids plus one phosphate group
16
Q
Formation of lactose:
A
- Glucose + galactose
- Joined by condensation reaction
- Joined by glycosidic bonds
- Added to polypeptide in golgi apparatus = glycoprotein
17
Q
Non- competitive inhibitor:
A
- Binds to an area other than the active site
- Changes shape of active site
- No longer complementary so less E-S complexes form
18
Q
Benefits and disadvantages of more hedgerows:
A
- Greater biodiversity so increase in predators of pests
- More difficult to farm so less income
19
Q
Stabilising selection:
A
- extreme (feature) less likely to survive and reproduce and so less likely to pass on their alleles
- (feature) decreases in frequency
- alleles decrease in frequency
20
Q
Structure of HIV:
A
- RNA
- reverse transcriptase
- capsid
- phospholipid envelope
- attachment proteins
21
Q
Elisa test:
A
- add antibody to cells
- wash to remove excess antibody
- add second antibody with enzyme attached
- add substrate to cause colour change
22
Q
How plants could survive without xylem:
A
- short diffusion pathway (for water)
23
Q
Leaf growth on xerophytic plants:
A
- slow growth
- due to smaller number of stomata
24
Q
Why slow growth with very little water in soil:
A
- stomata close (to prevents transpiration)
- Less CO2 uptake so less photosynthesis
25
P Values and null hypothesis:
Probability that difference is due to chance is less than 0.05
Null hypothesis can be rejected, in these cases
26
Hydrolysis:
Breaks chemical bond between monomers and uses water
27
Condensation:
Joins monomers together and forms a chemical bond and releases water
Examples:
Beta glucose and cellulose
Alpha glucose and starch
28
Monomer definition:
small, repeating unit from which larger molecules are made
29
Test for non reducing sugar:
- Heat with acid and neutralise
- Heat with benedicts
- Red precipitate
30
Differences between cellulose and glycogen:
- cellulose is made of beta glucose and glycogen is made of alpha glucose
- cellulose has straight chains and glucose is branched
31
Features of starch that make it a good storage molecule:
- Branched so makes molecule compact
- insoluble so does not affect water potential
- polymer of a glucose so provides glucose for respiration
- large so can't cross cell membrane
32
Explain how the structure of protein is determined by amino acids it contains:
- structure is determined by the position of amino acids
- primary structure is the sequence of amino acids
- secondary structure is formed by hydrogen bonding
- tertiary structure formed by disulfide bridges
- quaternary structure contains one or more polypeptide chain
33
Bonds between amino acids:
- one amine group joins to carboxyl to forma peptide bond
- condensation reaction
34
Active site of an enzyme causes a high rate of reaction:
- lowers activation energy
- induced fit causes active site to change shape
- emzyme-substrate complex causes bonds to break
35
Biochemical test for protein:
- add bieuret reagent
- (sodium hydroxide + copper II sulfate solution)
36
Dipeptide similarities and differences:
- Amine group and carboxyl group (same)
- Variable r groups (different)
37
Structure of DNA:
- Polymer of nucleotide
- Each nucleotide formed from deoxyribose, phosphate group and nitrogenous base
- phosphodiester bond between adjacent nucleotides
- double helix
- hydrogen bonds between adenine, thymine, cytosine and guanine.
38
How phosphodiester bond forms:
- Condensation reaction
- Phosphate and deoxyribose
- catalysed by DNA polymerase
39
Why does DNA polymerase work in opposite directions:
- DNA has antiparallel strands
- Shape of the nucleotides is different
- Enzymes have active sites with specific shapes
- Only the 3' end can bind with active site of enzyme
40
Why nucleotides can only be added in a 5' to 3' direction:
- DNA polymerase
- is specific
- only complementary to 5' end
- shapes of 5' end and 3' end are different
41
Formation of an ATP molecule:
- Adenine, ribose and three phosphate molecules
- Condensation reaction
- ATP synthase
42
Five properties of water that are important for organisms:
- A metabolite in condensation reactions
- a solvent so reactions can occur
- High specific heat capacity so buffers change in temp.
- Large latent heat of vaporisation so provides a cooling effect
- Cohesion so supports columns of water
43
Role of membrane-bound ATP hydrolase enzyme:
- Hydrolyse of ATP into ADP and Pi releases energy
- allows active transport of ions
44
Gene mutation and potential benefits:
- change in base sequence
- results in the formation of a new allele
- mutation might be in an intron
- may result in increased survival
45
Definition of a tumor:
- uncontrolled cell division
- results on mass of abnormal cells
46
Result of death of alveolar cells in lungs:
- reduced surface area
- increased distance for diffusion
- reduced rate of gas exchange
47
Contrasting structure of animal and prokaryotic cells:
- Nucleus v free DNA
- mitochondria v none
- endoplasmic reticulum v none
- no cell wall v murein cell wall
- DNA bound to histones v DNA not associated
- linear DNA v circular DNA
48
How are triglycerides formed:
- One glycerol and three fatty acids
- Condensation reaction and removal of three molecules of water
- Ester bond formed
49
Phagocytosis of ADC (drug):
- Cell engulfs ADC
- Lysosome fuses with vesicle
- Lysozomes digest ADC to release drug
50
Prophase:
- Chromosomes condense
- Centromeres attach to spindle fibres
51
Metaphase:
- Chromosmes line up at equator of cell
52
Anaphase:
- Centromeres divide
- chromosomes pulled to opposite ends of cell
53
How can chloroplasts be isolated:
- Homogenise and filter
- cold, isotonic and buffered solution
- Centrifuge and remove cell debris
- centrifuge at higher speeds until chloroplasts settle out
54
Translation:
- mRNA attaches to ribosomes
- tRNA brings specific amino acid
- tRNA anticodon binds to complementary codon on mRNA
- Amino acids join to form peptide bond
- with the use of ATP
55
Aseptic techniques:
- Sterile spreader
- flame neck of bottle
- lift agar plate at an angle
- work close to upward air movement
- disinfect surfaces
56
Viral replication:
- attachment proteins attach to receptors
- viral nucleic acid enters cell
- reverse transcriptase makes DNA from RNA
- cell produces viral proteins
57
Different amino acids can catalyse same reaction because:
- Both active sites have same tertiary structure
- Form enzyme-substrate complexes
58
Immune response:
- helper T cell binds to antigen
- Helper t cell stimulates specific b cell
- b cell divides by mitosis
- forms plasma cells that release antibodies
59
How to classify organisms:
- Base sequence of DNA
- base sequence of mRNA
- Amino acid sequence
60
Adaption's of an insects tracheal system:
- Tracheoles have thin walls so short diffusion distance to cells
- highly branched so short diffusion distance to cells
- highly branched so large surface area for gas exchange
61
TEM v optical microscopes:
- uses electrons v no electrons
- greater resolution v lower resolution
- only dead specimens v can view live specimens
- does not show colour v shows colour
- thinner specimens
62
Features of conservative replication:
- weak hydrogen bonds between bases allows the two strands to separate easily
- two strands so both can act as templates
- complementary base pairing allows for accurate replication
63
Counter-current system in fish:
- water and blood flow in opposite directions
- maintains conc. gradient of oxygen
- along length of lamallae
64
Meiosis:
- DNA replication
- separation of homologous chromosomes in first division
- separation of sister chromatids in second
- produces 4 cells
65
Process of denaturation at high temperatures:
- More kinetic energy
- breaks hydrogen bonds
- changes shape of active site so fewer enzyme substrate complexes form
66
How bacteria replicate:
- binary fission
- replication of circular DNA
- division of cytoplasm to produce 2 daughter cells
- each with a single copy of DNA
67
More salt in blood plasma results in a build up of tissue fluid:
- higher salt results in lower water potential of tissue fluid
- less water returns to capillary by osmosis
68
Why iron deficient plants have a reduced rate of growth:
- Less thylakoid membrane
- Less chlorophyll
- Reduced light absorption
- slower rate of photosynthesis
69
Stages of drug trials:
- Tested on other mammals to check for side effects
- Tested on healthy humans to check for side effects
- Investigate different concentrations to find safe dosage
70
Why binding might increase rate of reaction:
- binding alters tertiary structure of enzyme
- active site changes shape slightly
- more E-S complexes form
71
Role of ATP in translation:
- provides energy
- peptide bonds form between amino acids
72
Role of Golgi apparatus:
- modifies triglycerides
- combines triglycerides with proteins
73
Role of the heart in the formation of tissue fluid:
- contraction of ventricles produces high hydrostatic pressure
- forces water out of blood capillaries
74
Process of crossing over:
- homologous pairs of chromosomes form a bivalent
- chiasma form
- alleles are exchanged
- producing new combinations of alleles
75
DNA vs mRNA:
- DNA has deoxyribose and mRNA has ribose
- DNA has thymine and mRNA has uracil
- DNA long and mRNA short
- DNA is double stranded and mRNA is single stranded
-
76
Found in bacteria but not plant cells:
- circular DNA
- murein cell wall
77
Explain a property of iron ions that enables these ions to carry out their role in red
blood cells:
- part of haem group
- binds with oxygen
78
Outline the role of organelles in the production, transport and release of proteins from
eukaryotic cells:
. DNA in nucleus is code (for protein);
2. Ribosomes/rough endoplasmic reticulum
produce (protein);
3. Mitochondria produce ATP (for protein
synthesis);
4 Golgi apparatus package/modify;
OR
Carbohydrate added/glycoprotein produced by
Golgi apparatus;
5 Vesicles transport
OR
Rough endoplasmic reticulum transports
79
complete digestion of starch by a mammal:
- hydrolysis
- of glycosidic bonds
- starch to maltose by amylase
- maltose to glucose by maltase
- membrane bound disaccharides
80
Structure of bacteria v HIV:
- both have RNA
- bacteria has a cell wall
- both have enzyme molecules
- HIV has capsid
81
Quantitative Benedict’s tests to produce a calibration curve of
colorimeter reading against concentration of maltose:
Make/use maltose solutions of
known/different concentrations
(and carry out quantitative
Benedict’s test on each);
2. (Use colorimeter to) measure
colour/colorimeter value of each
solution and plot calibration
curve/graph described;
3. Find concentration of sample from
calibration curve;
82
vaccine leads to production of antibody against HPV:
Vaccine/it contains antigen (from
HPV);
2. Displayed on antigen-presenting cells;
3. Specific helper T cell (detects antigen
and) stimulates specific B cell;
4. B cell divides/goes through
mitosis/forms clone to give plasma
cells;
5. B cell/plasma cell produces antibody;
83
Features of xerophytic plants:
1. Hairs so ‘trap’ water vapour
and water potential gradient
decreased;
2. Stomata in pits/grooves so
‘trap’ water vapour and water
potential gradient decreased;
3. Thick (cuticle/waxy) layer so
increases diffusion distance;
4. Waxy layer/cuticle so reduces
evaporation/transpiration.
5. Rolled/folded/curled leaves so
‘trap’ water vapour and water
potential gradient decreased;
6. Spines/needles so reduces
surface area to volume ratio;
84
Features of xerophytic plants:
- thick waxy layer so increases diffusion distance
- waxy layer so reduces transpiration
- hairs so 'traps' water vapour and water potential decreased
85
Less iron for plants means:
- less thylakoid membrane
- less chloropyll
- reduced light absorption
- slower rate of photosynthesis
86
Stages of drug trials before use:
- tested on other mammals to check for side effects
- tested on healthy humans for side effects
- investigate different conc. to find safe dosage
87
Non - overlapping:
- each codon is separate and read in sequence
88
degenerate:
- more than one codon can code for a single amino acid
89
universal:
- some codons code for same amino acids across all organisms
90
How a triglyceride forms the cell membrane:
- phosphate group is hydrophilic
- fatty acid tails are hydrophobic
- forms a phospholipid bilayer
- heads facing water
91
Why antibiotics do not work on viruses:
- do not have metabolic processes
92
Importance of keeping xylem vessels open:
- allows unbroken water column
- cohesion from hydrogen bonds between water molecules
- transpiration creates tension
93
Role of golgi apparatus:
- forms lysosomes
- modifies lipids
94
why insert into spinal fluid/blood:
- quickly reaches spinal cord
- broken down by enzymes
95
Species richness definition:
- number of different species in a community
96
humoral response:
- b cells (specific to..) divide/reproduce by mitosis
- produce plasma and memory cells
97
What is a gene?
- sequence of DNA bases that codes for a polypeptide
98
Change in environmental conditions that would increase shelf life
- reduced light intensity
- stomata close
- decreased rate of transpiration
99
how does the structure of the insect gas exchange system:
- provide cells with sufficient oxygen
- limits water loss
- spiracles close so less water loss
- highly branched tracheoles so short diffusion distance to cells
- spiracles, tracheae, tracheoles
- spiracles allow diffusion of oxygen
- tracheoles are highly branched so large surface area for gas exchange
- tracheoles have thin walls so short diffusion distance
- tracheoles are permeable to oxygen
100
non-disjunction
- in meiosis
- chromosomes not separated
101
Function and benefit of extracellular proteases:
- to digest protein
- so can absorb amino acids for growth
102
Actions of membrane bound dipeptidases:
- to hydrolyses peptide bonds to release amino acids
- so amino acids can cross cell membrane
103
how water from tissue fluid returns to capillary:
- plasma proteins remain (in blood)
- reduces water potential of blood
- water moves to blood by osmosis
- returns to blood by lymphatic system
104
Advantage of the Bohr effect during intense exercise:
- increases dissociation of oxygen
- for aerobic respiration at the tissues
- to delay anaerobic respiration at the tissues
105
Binding of one molecule of oxygen to haemoglobin makes it easier for a
second oxygen molecule to bind:
- binding of first oxygen changes tertiary structure of haemoglobin
- creates another binding site
106
method other than colorimeter to measure amount of reducing sugar:
- filter and dry
- find weight
107
How a competitive inhibitor decreases rate of reaction:
- inhibitor similar shape to active site
- binds to active site
- prevents enzyme-substrate complexes forming
108
Types of diffusion:
- simple diffusion of non-polar molecules down a conc. gradient
- facilitated diffusion down a conc, gradient via channel protein
- osmosis of water down a water potential gradient
- active transport against a conc, gradient via protein carrier and using ATP
- co transport of 2 different substances using a carrier protein
