Mock Paper 2 Flashcards

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1
Q

Evolution (11)

A
  • evolution occurs when heritable characteristic of a species change
  • speciation is the development of a new species from a pre-existing species over time
  • variation is differences between organisms of the same species
  • Causes of variation are meiosis, random fertilisation, and mutation
  • overproduction - more young than will survive
  • selective pressure - competition for resources
  • variations - individuals vary from one another
  • survival of the fittest phenotype - individuals with favoured characteristics will survive and pass on genes
  • favourable characteristics increase
  • reproductive isolation of separated population
  • geographical isolation leads to speciation
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2
Q

Outline functions of RER and Golgi Apparatus

A
  • ribosomes if RER produce proteins
  • proteins from RER are for secretion outside cell
  • Golgi modifies proteins
  • Exocytosis of proteins in vesicles from the Golgi
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3
Q

Outline the control of metabolism by end-product inhibition

A
  • metabolic pathway is a chain of enzyme-catalyzed reactions
  • non-competitive inhibition
  • negative feedback
  • Changes shape of active site
  • Inhibits first enzyme in pathway
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4
Q

Explain how hydrophobic and hydrophilic properties contribute to the arrangement of molecules in a membrane.

A
  • phospholipid bilayer
  • hydrophilic is attracted to what, hydrophobic is not
  • hydrophilic head faces outwards
  • hydrophobic tails face inwards
  • cholesterol is amphipathic and located in phospholipids
  • hydrophobic proteins in phospholipid bilayer
  • hydrophilic proteins are on membrane surface - peripheral proteins
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5
Q

Outline the process of inhalation in humans

A
  • diaphragm and external intercostal muscles contract
  • as volumes increases, pressure decreases
  • air enters lungs due to high atmospheric pressure
    -diaphragm moves down
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6
Q

Describe the function of valves in mammalian hearts

A
  • prevents backflow
  • open valves allow blood to flow through
  • closed semilunar valve allows ventricles to fill with blood
  • AV valves prevent backflow from ventricle to atrium
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7
Q

explain how blood solute concentration are kept within narrow limits in the human body

A
  • solute concentration is monitored by hypothalamus
  • pituitary releases ADH
  • ADH is released when solute concentration is too high
  • Collecting duct becomes more permeable
  • water is reabsorbed
  • negative feedback
  • small volume of urine produced with ADH
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8
Q

Outline the roles of helicase and ligase in DNA replication

A
  • helicase unwinds DNA
  • helicase breaks hydrogen bonds
    -ligase joins Okazaki fragments
  • ligadles makes Covent bonds between nucleotides
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9
Q

Outline features of an ecosystem that makes them sustainable

A
  • water supplied by rainfall
  • sun provides energy
  • decomposes break down organic matter
  • recycling nutrients
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10
Q

Compare and contrast prokaryotes and mitochondria

A
  • prokaryote has a cell wall, mitochondria does not
  • prokaryotes is single membrane, mitochondria is double
  • both have 70S ribosomes
  • Both rod shaped
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11
Q

Histones

A
  • Histones package the DNA into nucleosomes
  • nucleosomes consists of a strand of DNA coiled around 8 histone proteins
  • nucleosomes helps supercoil DNA
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12
Q

Outline 4 types of membrane transport, including their use of energy

A
  • simple diffusion is passive movement if molecules along a concentration gradient
  • facilitated diffusion is passive movement of molecules along a concentration gradient through protein channels
  • osmosis is the passage of water through a membrane from a region of low solute concentration to a region of high solute concentration
  • active transport is the movement of molecules against the concentration gradient through membrane pumps with the use of ATP
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13
Q

Draw the structure of a dipeptide

A

Check word

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14
Q

Explain the cause of sickle cell anaemia and how this disease affects humans

A
  • caused by base substitution from GAG to GTG
  • mRNA copies the mutation
  • change in the shape of RBC
    -blocks blood flow
  • sickles RBC can’t carry oxygen leading to fatigue
  • provides protection against malaria
  • homozygous is Sever
  • Heterozygous is minor
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15
Q

Outline energy flow through a food chain

A
  • energy from the sun is converted into chemical energy by photosynthesis
  • heat is lost
  • energy lost in hair, bones, faeces
  • energy transfer is only 10% between trophic levels
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16
Q

Draw a fully labelled graph of the action spectrum for photosynthesis

A

Check word