𝐈 - 𝐤𝐞𝐲 𝐜𝐨𝐧𝐜𝐞𝐩𝐭𝐬 𝐢𝐧 𝐛𝐢𝐨𝐥𝐨𝐠𝐲

• what are all living things made up of?

  cells.
• what type of cell is an animal cell?

  eukaryotic.
• what type of cell is a plant cell?

  eukaryotic.
• what type of cell is a bacterial cell?

  prokaryotic.
• what is the difference between a eukaryotic and prokaryotic cell?


  eukaryotic cells have a nucleus, prokaryotic cells don't.
• what subcellular structures are in an animal cell?


  ~ nucleus.

  ~ cytoplasm.

  ~ cell membrane.

  ~ mitochondria.

  ~ ribosomes.
• what is the function of a nucleus?


  contains genetic material that controls the activities of the cell. genetic material is arranged into chromosomes.
• what is the function of cytoplasm?


  gel-like substance where most of the chemical reactions happen. contains enzymes that control these chemical reactions.
• what is the function of cell membrane?


  holds the cell together and controls what goes in and out.
• what is the function of mitochondria?


  where most of the reactions for respiration take place. respiration transfers energy that the cell needs to work.
• what is the function of ribosomes?


  involved in translation of genetic material in the synthesis of proteins.
• what subcellular structures are in a plant cell?

  everything from an animal cell, plus;

  ~ rigid cell wall.

  ~ large vacuole.

  ~ chloroplasts.
• what is the function of the cell wall?

  made of cellulose. supports the cell and strengthens it.
• what is the function of the vacuole?


  contains cell sap, a weak solution of sugar and salts. maintains the internal pressure to support the cell.
• what is the function of chloroplasts?

  photosynthesis occurs, which makes food for the plant. contains a green substance called chlorophyll.
• what subcellular structures are in a bacterial cell?

  ~ chromosomal DNA.

  ~ ribosomes.

  ~ cell membrane.

  ~ plasmid DNA.

  ~ flagella.
• what is the function of chromosomal DNA?


  controls the cell's activities and replication. floats free in the cytoplasm.
• what is the function of plasmid DNA?


  small loops of extra DNA that aren't part of the chromosome. contains genes for things like drug resistance and can be passed between bacteria.
• what is the function of flagella?


  a long, hair-like structure that rotates to make the bacterium move. can be used to move away from the bacteria away from harmful substances like toxins and towards beneficial things like nutrients or oxygen.
• what is a specialised cell?


  cell that has a structure which makes it adapted to its function.
• what are egg and sperm cells specialised for?


  reproduction.
• what are the main functions of an egg cell?


  to carry the female DNA and to nourish the developing embryo in the early stages.
• how is an egg cell adapted to its function?


  ~ contains nutrients in the cytoplasm to feed the embryo.

  ~ has a haploid nucleus.

  ~ straight after fertilisation, its membrane changes structure to stop any more sperm getting in to make sure the offspring ends up with the right amount of DNA.
• what is the main function of a sperm cell?

  to transport the male's DNA to the female's egg.
• how is a sperm cell adapted to its function?


  ~ has a long tail so it can swim to the egg.

  ~ has lots of mitochondria in the middle section to provide the energy needed to swim.

  ~ has an acrosome at its 'head' where it stores enzymes needed to digest its way through the membrane of the egg cell.

  ~ contains a haploid nucleus.
• what is a ciliated epithelial cell specialised for?

  moving materials.
• where can you find ciliated epithelial cells?

  lining of the airways.
• what is cilia?


  a hair-like structure on the top surface of an epithelial cell.
• how is a ciliated epithelial cell adapted to its function?

  cilia beat to move substances in one direction, along the surface of the tissue.
• why are there ciliated epithelial cells in the lining of the airways?

  help to move mucus up the throat so it can be swallowed and doesn't reach the lungs.
• what are microscopes used for?

  to magnify images and increase the resolution (how well a microscope distinguishes between two points that are close together) of an image.
• what are the advantages of using an electron microscope?


  ~ use electrons rather than light.

  ~ higher magnification and resolution.

  ~ can see smaller things in more detail.

  ~ greater understanding of how cells work and the role of subcellular structures.
• how do you prepare a microscope slide?


  ~ take a thin slice of your specimen.

  ~ take a clean slide and use tweezers to place your specimen.

  ~ add a drop of methylene blue dye to stain your specimen.

  ~ place a cover slip gently so there are no air bubbles.
• how do you view a specimen using a light microscope?

  ~ clip your slide to the stage.

  ~ select the lowest powered objective lens.

  ~ use the coarse adjustment knob.

  ~ use the fine adjustment knob.

  ~ swap to a higher powered objective lens.
• how do you create a scientific drawing of a specimen?


  ~ use a sharp pencil to draw outlines of main features.

  ~ keep parts in proportion.

  ~ label important features with straight lines.
• what is magnification?


  how many times bigger the image is.
• how do you work out the total magnification?

  eyepiece lens magnification multiplied by objective lens magnification.
• how do you work out the real size of a specimen?

  image size divided by magnification.
• how do you convert millimetres (mm) to micrometres (µm)?

  multiply by 1000.
• how do you convert micrometres (µm) to nanometres (nm)?

  multiply by 1000.