biology paper 1

• oxygenated blood goes from the lungs to the heart then to the rest of the body via arteries
• the heart is made up of four chambers - two atria (top) and two ventricles (bottom)
• deoxygenated blood comes back to the heart through veins, then to the lungs via pulmonary artery
• what is a gamete?

  • a reproductive cell of an animal or a plant
• how do enzymes work?

  • involve taking a reactant (substrate) and breaking apart into smaller pieces
  • multiple substrates turn into a single product
  • all enzymes do in these cases is speed up the process
  • enzymes have a special region called the active site which a unique shape complimentary to the substances
  • if substrate doesn't fit active site, reaction wont be catalysed, allows energy to be specific about the reactions they speed up
• give 2 reasons why blood clotting is important

  • prevents blood from leaving bloodstream
  • prevents microorganisms from entering bloodstream which could cause infection
• why do animals prefer aerobic respiration to anaerobic respiration

  • anaerobic respiration doesn't break down glucose molecule completely so less energy is released
  • anaerobic respiration produces lactic acid which can damage cells and also lead to oxygen debt (causes cramps as well)
• what are the steps of mitosis and cytokinesis

  • DNA condenses to form chromosomes
  • chromosomes line up along the centre of cell
  • cell fibres pull the two arms of each chromosome to opposite sides (poles) of the cell
  • cytokinesis- the entire cell divides to form two identical daughter cells
• name the 4 components of blood

  • white blood cells
  • red blood cells
  • platelets
  • plasma
• what is the role of red blood cells in the body?

  • red blood cells carry oxygen around the body
• what is a gene?

  • small section of DNA that codes for a protein
• what is asexual reproduction?

  Reproduction without the involvement of gametes or the fusion of genetic material from two parents.
• what is a metabolism?


  The process by which the body converts food and drink into energy.
• what is a prokaryotic cell + example

  • a prokaryotic cell isa microorganism that doesn't have a membrane bound nucleus. E.g. bacteria
• what is a eukaryotic cell + example

  • a eukaryotic cell is a micro organism that has a membrane bound nucleus. e.g. animal cell
• what is blood plasma?

  • a yellow liquid within blood that transports substances around the body
• how do plants get the water required for photosynthesis?

  • water diffuses into the roots via osmosis
• what is the definition of homozygous

  • two of the same alleles
• what is the definition of heterozygous

  • two different alleles
• what is an organ

  • group of tissues that work together to perform a particular function
• what is an organ system

  • a group of organs that work together to perform a particular function
• how do plants get the carbon dioxide needed for photosynthesis

  • diffuses into the leaves via stomata
• which substances are dissolved in blood plasma

  • waste products- carbon dioxide, urea
  • nutrients- glucose, amino acids, fatty acids, glycerol
  • antibodies/hormones
• what is a pathogen

  • microorganism that causes disease
• what is an enzyme

  • biological catalyst
  • made by living organisms
  • basically large proteins
• what is a catalyst

  • a substance that speeds a reaction without being charged or used up in the process
• what is a genome

  • entire set of genetic material in an organism
• what is a genotype

  • entire collection of alleles we have
• what is a phenotype

  • characteristics you get from your genotype
• what is the role of mitochondria

  • aerobic respiration
  • release energy for cells to use
• what are the functions of aveoli

  • adapted for gas exchange
• what is the function of an alveoli

  • site of gas exchange
• what is a haploid cell

  • cell that contains only half the genetic material
• what is mitosis

  • where 2 identical cells are created~
  • they are diploid (both sets of chromosomes, 23 pairs)
• what is meiosis

  • where sex cells are creates -(pollen , ovum , sperm , egg)
  • they are genetically different cells
• what is osmosis

  • the movement of water from a high to low concentration through a semi permeable membrane
• what is diffusion

  • the process where particles spread and move from an area of high concentration to an area of low concentration
• factors affecting diffusion

  • temp
  • surface area of the membrane
• what is active transport

  • active transport is the process where particles move from a more dilute solution to a more concentrated solution, requiring energy from cell respiration
• what are the 5 stages of cell division

  • interphase - (cell spends most of its time in this phase , duplicating DNA)
  • prophase - (chromosomes split up and condense into each of the 46 chromosomes)
  • metaphase - (chromosomes line up at the middle of the cell)
  • anaphase - (chromosomes are being pulled apart)
  • telophase + cytokinesis -(new nucleus is created and the chromosome split apart