past paper bio

Subdecks (1)

Cards (181)

  • Describe what happens during fertilisation
    sperm and egg nuclei fuse/ gamete nuclei fuse
  • What is formed in fertilisation
    diploid zygote
  • what is meant by chromosome complement
    zygote has two sets of chromosome
  • Most features of an individual phenotype are
    polygenic and show continuous variation
  • Which term describes the type of variation in which a characteristic is controlled by more than one gene?
    continuous
  • State the type of variation shown by tongue-rolling.
    discrete
  • Explain what is meant by the term homozygous.
    (both) alleles are the same/identical
  • State a feature of the cell membrane which allows the movement of only some substances into the cell.
    selectively permeable/ contains proteins
  • Describe the effect of osmosis on a leaf cell if it was placed in pure water
    The cell would become turgid
  • Describe the effect of osmosis on a red blood cell if it was placed in pure water.
    cell would burst
  • What is the definition of diffusion
    movement of molecules from a higher concentration to a lowe concentration
  • What is the definition of active transport
    Movement of moelcules/ions from a low to a high concentration against a concentration gradient
  • Enzymes such as lactase are biological catalysts. Explain the role of enzymes in living cells.

    speed up chemical reactions
  • name the substance of which enzymes are made.
    proteins/amino acids
  • Explain why the fermenter must be sterilised using aseptic techniques before it is used.
    To ensure there are no other bacteria present
  • The fermenter is controlled to provide optimum conditions. Name one factor which can be controlled.
    temperature/ pH
  • Explain why muscle cells require many mitochondria
    requires a lot of energy for movement/ contraction
  • name one substance produced by a cell carrying out aerobic respiration.

    carbon dioxide/ water/ (2) ATP
  • A muscle cell will carry out fermentation when oxygen is not available. Describe the fermentation pathway in muscle cells. (3)
    • glucose converted into pyruvate
    • pyruvate converted to lactic acid
    • 2ATP produced
  • function of cytoplasm
    site of chemical reactions
  • the bases in a strand of DNA make up the code for the production of proteins. The DNA for every individual person varies.
    Describe how this code differs from person to person.
    sequence/order of bases
  • what is a source of new alleles in a population
    mutations
  • It is a biotic factor and causes a decrease in prey numbers. is what factor
    predation
  • Function of sensory neuron

    carries/sends message/impulses/signal from sense organ relay neuron/CNS/spinal cord
  • function of motor neuron
    carries/sends message/impulse/signal from CNS to muscle/effector
  • function of relay neuron
    carries/sends message/impulse/signal from sensory to motor neuron/within CNS
  • describe how information is passes along a neuron
    electrical impulse
  • most features of an individuals phenotype are controlled by more than one gene
    polygenic
  • describe the structures and processes involved as water moves through plants from soil to the air
    Water is absorbed by root hairs by osmosis/diffusion (1)
    (Water) travels upwards in the xylem (1)
    (water) travels to the stomata and diffuses out
  • describe two features of these sturctures which improve the efficiency of gas exchange
    • large surface area
    • thin walls/ walls are one cell thick
    • rich blood supply/ dense capillary network
    • moist
  • describe how mucus and cilia work together to prevent bacteria getting into the lungs
    Dirt/dust/ microrganisms are trapped in the mucus
    Cilia move these up and away from the lungs
  • why is nitrates important to plants
    needed to make proteins
  • name a site of mitosis in plants
    meristem/root tip
  • when writing percentage change for increase you must include...
    +
  • suggest why the eggs were blotted dry before reiweighed
    to remove excess water on the eggs so it wont alter mass
  • describe one difference between passive and active transport
    passive transport moves down a concentration whereas active transport goes against a concentration gradient
  • DNA contains genetic material which controls the synthesis of chemical made from amino acids. Name the chemical synthesised
    protein
  • Give description of what mRNA is
    Messanger RNA is an order/sequence of bases (which determine base/sequence of amino acids)
  • wheres is mRNA made
    nucelus
  • name two products used in second stage of photosynthesis
    hydrogen and ATP