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A-Level Biology > Paper 1 - 1/2/3/4 > Flashcards

Paper 1 - 1/2/3/4 Flashcards

Important definitions and equations - no processes or practical stuff (98 cards)

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1
Q

Define polymer

A

Large molecule made up of many repeating units of monomers joined together by chemical bonds

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2
Q

Define monomer

A

Smaller units that combine to make a large molecule (polymer)

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3
Q

Define consendation reaction

A

the removal of a water molecule to form a chemical bond between two molecules

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4
Q

Define hydrolysis reaction

A

the addition of a water molecule to break a chemical bond between two molecules

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5
Q

Define monosaccharide

A

monomer used as an energy source; glucose (alpha/beta), fructose, galactose

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6
Q

Define disaccharide

A

two molecules join in a condensation reaction to form a glycosidic bond - transport molecule

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7
Q

Define maltose

A

condensation reaction between two monosaccharides of alpha glucose

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8
Q

Define sucrose

A

condensation reaction between two monosaccharides alpha glucose and fructose

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9
Q

Define lactose

A

condensation reaction between two monosaccharides alpha glucose and galactose

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10
Q

Define polysaccharide

A

a polymer of a monosaccharide; cellulose, glycogen, starch

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11
Q

Describe starch (amylose)

A

where; plants
which monomer; alpha-glucose
which bonds; 1-4
branched? no

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12
Q

Describe starch (amylopectin)

A

where; plants
which monomer; alpha-glucose
which bonds; 1-4 and 1-6
branched? yes

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13
Q

Describe cellulose

A

where; plants
which monomer; beta-glucose
which bonds; 1-4
branched? no

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14
Q

Describe glycogen

A

where; animals
which monomer; alpha-glucose
which bonds; 1-4 and 1-6
branched? yes

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15
Q

Describe the test for reduced sugars

A

equal volume of the food sample and Benedict’s solution and place in a water bath
positive result; change from blue (to green to yellow) to red ppt

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16
Q

Describe the test for non-reduced sugars

A

add hydrochloric acid and heat in a water bath, neutralise with NaOH
use the Benedict’s test

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17
Q

Describe the test for starch

A

add iodine
positive result; orange to blue-black

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18
Q

Describe the test for lipids

A

equal volume of the food sample and ethanol, shake, and add distilled water
positive result; milky white emulsion

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19
Q

Describe triglycerides and their functions

A

one glycerol and three fatty acids bind in a condensation reaction through the removal of three water molecules per fatty acid to form an ester bond (non-polar)
they are used as an energy store - insoluble and the fatty acid tails have bonds that can be broken to release energy

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20
Q

Describe phospholipids and their functions

A

a phosphate and glycerol which makes up the hydrophilic head and two fatty acid tails which are hydrophobic - polar
used as a structural component of the membrane as they form a bilayer

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21
Q

Describe the test for proteins

A

equal volume of biuret solution to the sample
positive result; blue to purple

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22
Q

describe the lock and key model

A

the complementary substrate fits exactly into the enzymes active site

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23
Q

describe the induced fit model

A

the complementary substrate does not fit perfectly, it enters the active site and the active site changes slightly, this puts strain on the substrates bonds and lowers the activation energy

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24
Q

Define competitive inhibitor

A

they have a similar shape to the the substrate so bind to the active site
this prevents the substrate from binding, reducing the formation of enzyme substrate complexes
(most are reversible)

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25
Define non-competitive inhibitor
they bind to a separate binding site from the active site, changing the tertiary structure of the enzyme and changing the shape of the active site the enzyme is no longer complementary to the substrate to no enzyme-substrate-complexes form
26
describe the structure of a nucleotide
a phosphate, a pentose sugar and a nitrogenous sugar
27
which bases are the purines and which pyrimidines
Adenine and Guanine are purines as they have two rings Thymine and Cytosine are pyrimidines as they have one ring
28
Define conservative replication
a new copy is made from the original DNA which remains intact
29
define semi-conservative replication
DNA splits and each act as a template strand
30
Describe ATP's structure and properties
structure; adenine, ribose and triphosphate (3 Pi) properties; hydrolysis of ATP releases a small amount of energy, in one step - fast, can be rapidly re-synthesised, soluble so can be transported easily around cells
31
functions of water
solvent, buffers sudden temperature changes, evaporation of water in sweating cools, organisms live in water and breath in it, metabolic reactions (hydrolysis), transport - mass transport
32
what are features of specialised exchange surfaces
short diffusion pathways (thin walls), larger area for substances to be exchanged (larger surface areas), maintains a steep concentration gradient (good blood flow/ventilation)
33
why can't multicellular organisms just diffuse
cells don't have direct contact with the eternal environment diffusion distance is too large larger organisms have higher metabolic rate so need more oxygen and glucose
34
35
describe adaptions of insects gas exchange (trachea, tracheoles, spiracles)
trachea; multiple of them so increased surface area tracheoles; thin walls decreases diffusion pathway, highly branches to increase surface area spiracles; open and close to control gas exchange and minimise water loss
36
describe adaptions of fish gas exchange
gill filaments and lamellae increase surface area, extensive blood vessels, thin membranes, counter-current flow
37
describe adaptions of human gas exchange
thin walls - epithelial cells, large surface area, partially permeable (only O2 and CO2 can move across), good ventilation
38
Define Endopeptidases
hydrolyse internal peptide bonds in the polypeptides
39
Define Exopeptidases
hydrolyse outer peptide bonds of the polypeptides
40
Define Dipeptidases
hydrolyse dipeptides
41
Cardiac output=...
stroke volume (volumes of blood pumped out of left ventricle) times heart rate
42
Adaptation of xylem
hollow tubes without end walls, no organelle, lignin for support
43
Adaptation of phloem/companion cells
sieve plates have pores to allow amino acids and sucrose through, no nuclei, only a thin layer of cytoplasm companion cells have lots of mitochondria to release energy for active transport
44
Define prokaryotes
single-celled organisms without a nucleus or any membrane bound organelle
45
Define eukaryotes
multicellular organisms with a nucleus and membrane bound organelle
46
describe the structure and function of nuclei
structure; nuclear envelope with nuclear pores, chromatin and nucleolus function; controls cell and contains genetic material
47
describe the structure and function of the cell surface membrane
structure; phospholipid bilayer, lipids, proteins, cholesterol function; controls the movement of substances
48
describe the structure and function of mitochondria
structure; double membrane with folds called cristae filled with a fluid matrix (contain their own DNA) and has ribosomes function; site of aerobic repiration, produces ATP
49
describe the structure and function of Golgi apparatus
structure; fluid-filled, membrane-bound sacs known as cisternae and smaller vesicles function; Process and package lipids and proteins, store and transport lipids and proteins, synthesise lysosomes
49
describe the structure and function of ribosomes
structure; small and large sunbit function; protein synthesis (translation)
50
describe the structure and function of rough endoplasmic reticulum
structure; a network of membranes enclosing a fluid-filled space, known as cisternae covered with ribosomes function; synthesis and transport of proteins
51
describe the structure and function of smooth endoplasmic reticulum
structure; a network of membranes enclosing a fluid-filled space, known as cisternae function; synthesis, storage and transport of lipids and carbohydrates
52
describe the structure and function of lysosomes
structure; hydrolytic enzymes surrounded by a membrane function; digest pathogens and waste material
53
what organelle do plants have that animals don't
vacuole, cell wall, chloroplasts,
54
describe the structure and function of chloroplasts
structure; fluid-filled sacs known as thylakoids which are stacked up to form grana connected by lamellae, own DNA and ribosomes, double-membrane function; site of photosynthesis
55
gives the types of muscle
Smooth - Found in the walls of organs. Cardiac - Found in the heart. Skeletal - Found attached to bones.
56
name the prokaryotic organelle
plasmids, nucleoid (circular DNA), cell-surface membrane, cell wall, capsule, pili, flagellum, ribosomes
57
name the virus organelle
Always: Genetic material - Viral DNA or RNA and single or double-stranded, capsid - a layer of protein molecules that surrounds and protects the genetic material. Sometimes: Envelope, attachment proteins, Enzymes - reverse transcriptase
58
magnification=...
image/actual
59
define the fluid mosaic model
the bilayer moves fluidly, proteins imbedded make it appear like a mosaic
60
define facilitated diffusion
large polar molecules from an area of high concentration to an area of low concentration through a carrier or channel protein
60
define diffusion
the net movement of particles from an area of high concentration to an area of low concentration - small, non-polar molecules
61
define osmosis
movement of water molecules across a partially permeable membrane from an area of higher water potential to an area of lower water potential
62
describe an cell in a Hypotonic solution
solution has a higher water potential than the cell Water molecules move into the cell the cell swells and bursts
63
describe an cell in a Isotonic solutions
solution has the same water potential as the cell. There is no net movement of water into or out of the cell the cell stays the same size
64
describe an cell in a Hypertonic solutions
solution has a lower water potential than the cell. Water molecules move out of the cell the cell shrinks
65
Define active transport
the movement of particles from an area of lower concentration to an area of higher concentration requiring energy from the hydrolysis of ATP (carrier proteins)
66
define Agglutination
clumping pathogens together to enable easier phagocytosis
67
define monoclonal antibodies
antibodies produced from a single clone of plasma cells
68
define t helper cells
bind to complementary antigens on antigen-presenting cells, they can form memory cells, stimulate B cells or phagocytes, and activate cytotoxic T cells
69
define cytotoxic T cells
cells kill abnormal and foreign cells ( out of spec - by producing a protein known as perforin. This protein makes holes in the cell-surface membrane, causing it to become freely permeable and causing cell death)
70
define memory T/B cells
provide long-term immunity by recognising a specific antigen
71
define plasma cells
type of B cell that can produce and secrete antibodies
72
define B cells
cells have antibodies on their cell-surface membrane that bind to complementary antigens, they engulf the antigens and display them on their cell-surface to become antigen-presenting cells. Once activated, B cells can divide into plasma cells and memory cells
73
describe the primary immune response (first repsonse)
slow production of antibodies, the antibody concentration increases slowly as there are few B cells specific to the antigens symptoms experienced, takes long for antibody production (T/B cells)
74
describe the secondary immune response (second response)
fast production of antibodies, concentration increases quickly more memory cells recognise the antigens and divide into plasma cells plasma cells secrete large numbers of antibodies no symptoms, shorter time before antibody production (memory B/T cells)
75
describe the structure of tRNA
single-stranded clover-shape, anticodon, contains an amino acid binding site (smaller than mRNA, has H bonds and mRNA doesn't)
76
describe the structure of mRNA
single-stranded linear molecule, base sequence complementary to the DNA sequence, codons
77
describe two chromosome mutations
Polyploidy - when organisms have more than two sets of chromosomes Non-disjunction - when homologous chromosomes fail to separate in meiosis
78
describe stabilising selection
average phenotype is favoured as the graph narrows - extremes are cut off
79
describe directional selection
extreme phenotypes are favoured as the graph divides or shifts towards the favoured exteme
80
give the taxonomic system: Domain...
Domain Kingdom Phylum Class Order Family Genus Species
81
what are the three domains
Bacteria Archaea Eukarya
82
define habitat
where a species lives within an ecosystem
83
define Community
living organisms of all species found in a particular ecosystem at a particular time
84
define Ecosystem
interacting community of organisms and their environment
85
define Species richness
total number of different species in a habitat
86
define Species eveness
numbers of individuals of each species in a community
87
define interspecific (in bio context)
different species
88
define intraspecific (in bio context)
same species
89
conservation in agriculture
Maintaining hedgerows Reducing pesticide and herbicide use Using organic fertilisers Using crop rotation
90
define independent segragation
separating chromosomes into homologous pairs in random combinations
91
define crossing over
in prophase I, the homologous chromosomes condense and pair up before forming a chiasmata the chromosomes swap alleles and produce different combinations
92
adaptations of the vein
collagen - strength to prevent bursting thiner walls - as there's less pressure valves - prevent backflow
93
adaptations of the capillaries
lumen is very narrow so red blood cells can get close to respiring tissue thin walls for a shorter diffusion distance highly branched - larger surface area
94
adaptations of the arteries
collagen - strength to prevent bursting elastic fibres allows elastic recoil, smoothening the flow of blood to minimise pressure changes thick smooth muscle layer contracts/relaxes to constrict/dilate the lumen and control blood flow
95
define vasoconstriction
smooth muscle contracts, constricting the blood vessel and decreasing blood flow
96
define vasodilation
smooth muscle relaxes, dilating the blood vessel and increasing blood flow

A-Level Biology (6 decks)

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