Bio paper 1 ❤️

• Name & Function of the Sub-cellular Structures Inside an Animal Cell

  - Nucleus - contains genetic material and constols the activities.

  - Cytoplasm - where most of the chemical reactions take place.

  - Cell Membrane - controls passage of substances in and out of the cell.

  - Mitochondria - where aerobic respiration takes place.

  - Ribosomes - where protein synthesis takes place.
• Name & Function of the Sub-cellular Structures Inside a Plant Cell

  - Nucleus - contains genetic material and constols the activities.

  - Cytoplasm - where most of the chemical reactions take place.

  - Cell Membrane - controls passage of substances in and out of the cell.

  - Mitochondria - where aerobic respiration takes place.

  - Ribosomes - where protein synthesis takes place.

  - Cell Wall - made from cellulose which strengthens the cell.

  - Permanent Vacuole - filled with cell sap and supports the plant.

  - Chloroplasts - where photosynthesis takes place.
• Prokaryotic Cell


  A much smaller cell where there is not a true nucleus, contains plasmids and does not contain mitochondria or chloroplasts.
• Eukaryotic Cell


  A larger cell which contains a nucleus. E.g. animal and plant cells.
• Name & Function of the Sub-cellular Structures Inside a Bacteria Cell

  - Plasmid DNA - a small circular section of DNA that replicates independently.

  - Chromosomal DNA - the untrue nucleus.

  - Flagella - tail like structure to help movement.

  - Cell Wall - not made from cellulose but still provides structural support.

  - Cytoplasm - where most of the chemical reactions take place.
• Electron Microscope


  A microscope that focuses a beam of electrons to magnify objects.
• Light Microscope


  A microscope that uses a beam of light passing through one or more lenses to magnify an object.
• Magnification Calculation


  Image size/actual size.
• Microscopic Required Practical


  1) place a tissue sample on a microscope slide.

  2) add a few drops of stain.

  3) lower a coverslip onto the tissue.

  4) place the slide onto the microscope and focus on a low power.

  5) refocus on a high power.

  6) draw any type of cell which can be seen and add a scale line.
• Binary Fission


  A form of asexual reproduction in which one cell divides to form two identical cells.
• Culture Medium


  A nutrient material prepared for the growth of microorganisms in a laboratory. E.g. Agar
• Maximal Temperature Schools Should Store Microorganisms

  25°C
• Growing Microorganisms Required Practical

  1) get sterilised agar, Petri dish and a inoculating loop and pass it through a flame.

  2) transfer the bacteria to the agar by the cool inoculating loop.

  3) quickly add the lid to the Petri dish and store upside down so condensation doesn't drip onto the agar.
• Chromosome


  Found in the nucleus of a cell, they control the development of different characteristics. Humans have 23 pairs of them.
• Mitosis


  1) the cell grows and increases its number of au cellular structures.

  2) the DNA replicated to form 2 copies of each chromosome.

  3) one set of chromosomes are pulled to each end of the cell.

  4) the nucleus divides.

  5) the cytoplasm and cell membranes divide to form 2 identical daughter cells.
• Stem Cells


  These are undifferentiated cells which can divide to become any type of cell in the body. They are found in human embryos, in the umbilical cord of new born baby's, bone marrow and the meristem in plants.
• Uses of Stem Cells

  - therapeutic cloning.

  - too replace damaged cells.
• Diffusion


  Movement of molecules from an area of higher concentration to an area of lower concentration. Affected by temperature and surface area of membrane.
• Osmosis Required Practical


  1) cut some potato tissue cylinders and measure their mass.

  2) place cylinders in different concentrations of sugar solution.

  3) after about 30 mins remove the cylinders and measure their mass again. If a change in mass has occurred then osmosis has occurred.
• Osmosis


  Diffusion of water through a selectively permeable membrane, with the concentration gradient.
• Active Transport


  The movement of ions or molecules across a cell membrane from a low concentration to a high concentration, assisted by enzymes and requiring energy.
• Specialised Cells


  Cells that are adapted to carry out a particular function.
• Features of a Specialised Sperm Cell

  - packed with mitochondria to provide energy and increase respiration.

  - tail to propel the cell.

  - Acrosome contains enzymes to help it penetrate the outer layer of the egg.
• Features of a Specialised Muscle Cell

  - lots of mitochondria got energy for quick contraction.

  - protein fibres that can contract for quick contraction.
• Features of a Specialised Phloem

  - the ends of the cells allow sugars through but support the tubes.

  - Cells are arranged end to end in tubes.

  - contain companion cells
• Features of a Specialised Xylem

  - arranged end to end but the end walls break down to form hollow tubes.

  - Cell wall is strengthened by lignin.
• Features of a Specialised Root Hair Cell

  - lots of mitochondria for active transport.

  - long projection to increase surface area to absorb water and minerals.
• Tissue


  A group of similar cells that perform the same function.
• Organ


  A collection of tissues that carry out a specialized function of the body.
• Organ System


  A group of organs that work together in performing vital body functions.
• Organism


  Lots of organ systems working together to create a living thing.
• Enzymes


  These are biological catalysts which perform the lock and key theory. They are all large proteins, contain an active site and denature at 37°C.
• Enzyme Required Practical


  1) to test for sugars add Benedict solution and heat in a water bath for 2 minutes. If sugar is present it will turn red.

  2) to test for starch add iodide solution and if it is present it will turn a blue - black.

  3) to test for protein add butter reagent and of present

  Will turn purple.
• Amylase


  An enzyme produced in salivary glands and the pancreas. It is a carbohydrate that breaks down starch into sugars.
• Protease


  An enzyme produced in the stomach, pancreas and small intestine and it breaks down proteins into amino acids.
• Lipase


  An enzyme produced in the pancreas and small intestine and breaks down lipids into fatty acids and glycerol.
• Bile


  A liquid made in the liver and stored in the gall bladder. It is an alkaline that neutralised hydrochloric acid from the stomach. It also emulsified fats to form small droplets to increase the surface area for enzymes to act on.
• Effect of pH on Enzymes Required Practical

  1) put a test tube containing starch solution and a test tube containing amylase into a water bath at 37°C.

  2) after 5 mins add the amylase solution to the starch.

  3) every 30 secs take a drop from the mixture and test it for starch using iodine solution.

  4) record how long it takes for the starch to be completely digested.

  5) repeat at different pH values using different buffer solutions.
• Red Blood Cells


  Contain haemoglobin which binds yo oxygen to transport it from the lungs to working muscles.
• White Blood Cells


  Helps protect the body against infection and can change shape to engulf microorganisms.