National 5: Unit 1 revision

Chapter 1: Cell Structure Unit 1: Cell biology Chapter 1: Cell Structure

Questions What are the basic units of life? Draw and label an animal, plant, fungal and bacterial cell Write a comparison of a fungal cell and a green plant cell Write the function of the: Nucleus, Cytoplasm, Cell membrane, Mitochondria, Ribosomes, Cell wall, Vacuole, Chloroplasts, Large Circular chromosome, plasmid Explain why a plant’s root cells do not have chloroplasts How does the cell wall in a plant cell, fungal cell and bacterial cell compare?

Field of view In order to calculate the length of a cell, we can COUNT the number of cells along the DIAMETER of the microscope then perform a calculation. If there are 8 cells in the FIELD OF VIEW and the diameter is 2mm- How would we work out the length of one cell?

The diagram below shows onion cells as observed under a microscope at a magnification of 100 X. The diameter of the field of view is 300 micrometres. The average width of each cell in micrometres is A 0.38 B 0.75 C 375 D 75

The diagram below shows onion cells as observed under a microscope at a magnification of 100 X. The diameter of the field of view is 300 micrometres. The average width of each cell in micrometres is A 0.38 B 0.75 C 375 D 75

The diagram below shows a group of cells as seen under a microscope. The field of view was 2 mm in diameter. Calculate the average length and width of the cells. Average length __________ mm Average width __________ mm

The diagram below shows a group of cells as seen under a microscope. The field of view was 2 mm in diameter. Calculate the average length and width of the cells. Average length 0.4 mm Average width 0.2mm

Total magnification In order to work out the TOTAL MAGNIFICATION of a microscope we must multiply the power of the EYE PIECE LENS by the power of the OBJECTIVE LENS. If we know the TOTAL MAGNIFICATION we can use DIVISION to work out the strength of the EYEPIECE LENS or the OBJECTIVE LENS

Copy and complete x5 x60 x10 x35 x15 x65 x40 x400 x25 x275 Eye piece lens Objective lens Total magnification x5 x60 x10 x35 x15 x65 x40 x400 x25 x275

Chapter 2: Transport across cell membranes Unit 1: Cell biology Chapter 2: Transport across cell membranes

Plasma membrane Phospholipid Bilayer Fluid Mosaic Model Cell Membrane Controls entry and exit of substances into and out of cell Selectively permeable

Diffusion- definition, importance (uni/multi) Osmosis- definition, osmosis in action Active Transport- definition, examples

Name the two substances present in the cell membrane Draw and label a diagram of the cell membrane including the 2 substances mentioned Write down the definition of: Selectively permeable, Diffusion, Osmosis, Active Transport Explain why diffusion is important in: a) Unicellular b) Multicellular organism Give an example of a situation where a cell uses a) Diffusion b) Osmosis c) Active transport Define the terms passive and active Describe the role of the proteins in active transport Give an account of what happens to an animal cell placed in a) pure water b) isotonic solution c) salt solution

Chapter 3: Producing new cells Unit 1: Cell biology Chapter 3: Producing new cells

All living things contain genetic information Cell Nucleus 2 Matching sets of chromosomes Genes DNA

Chromosome Complement SEXUALLY reproducing animals have PAIRS Each species CHROMOSOME COMPLEMENT

Haploid and Diploid Every cell (except RBS and gametes) contain chromosome complement DIPLOID (2n)- 2 sets HAPLOID- (n)- 1 set

Cell Division (aka Mitosis) MITOSIS is the process by which the nucleus of a cell divides into TWO daughter nuclei, each of which contains EXACTLY the same number of chromosomes as the original parent cell.

Importance of Mitosis Unicellular- Reproduction Multicellular- Growth, Repair, Regeneration Diploid complement maintained- daughter cells have all the genes to function correctly

Stages of Mitosis

Loss of control Orderly process of cell division can go wrong DNA (oncogenes) can become damaged- MUTATIONS Cells don’t die when they should- new cells made but not needed Extra cells form TUMOUR

Examples of cancer causing agents! UV rays from the sun. UV rays from sun-beds, Chemicals in Cigarettes. Radiation. Diet. Lack of exercise. Chemicals such as DDT.

Cell culture When a supply of a certain type of cell is needed (stem cell, yeast or bacteria), Cultures of the cell can be grown.

Why cell culture? To learn about cell division Baking/brewing Testing drugs Stem cell research Grow new cells Diagnose illness

Cell culture To grow cells in the lab you need: A suitable growing medium Availability of oxygen A suitable temperature A suitable pH level Aseptic Conditions

What is a chromosome and where are they found in cells? Define the terms: a) Haploid b) Diploid c) Chromosome Complement What is the definition of mitosis? Explain why it is important that the chromosome complement is maintained during mitosis. Explain the importance of mitosis in a) Unicellular b) Multicellular organisms Using diagrams, give a description of each stage of mitosis State the role of the spindle fibres during mitosis Explain what can happen if control of cell division is lost What can increase the risk of loss of control of cell division? What can cell culture be used for? Explain why cell culture requires aseptic conditions Give 3 examples of what you can do to ensure aseptic conditions are maintained

Chapter 4: DNA and the production of proteins Unit 1: Cell biology Chapter 4: DNA and the production of proteins

DNA Chromosomes- Nucleus – made of DNA DNA- genetic code- recipe/blueprint

Structure of DNA DNA= TWO long stranded molecules Ladder Double Helix Monomer= NUCLEOTIDES

Nucleotides PHOSPHATE BASE (deoxyribose) SUGAR

Complementary Base Pairs Weak Hydrogen bonds between bases Complimentary base pairs- SHAPE Adenine-Thymine Guanine-Cytosine Always Together Good Company

Building Proteins Amino acids are building blocks of proteins 3 x bases= TRIPLET “Codeword” for AMINO ACIDS Approx 20 amino acids Amino acids join to make protein Order of amino acids determines protein

Protein Synthesis The genetic code in the DNA is copied by a messenger (mRNA) The mRNA carries a copy of the code out of the nucleus to the ribosomes The ribosomes select the correct amino acids. The amino acids are joined together to make a specific protein. Examples of proteins include hormones, enzymes, antibodies and structural proteins.

State the role of DNA in cells Describe the structure of DNA using the terms double helix and base Identify the 4 DNA bases What is meant by the term complimentary base pairs? What are the complimentary base pairs? What is the genetic code? How many amino acids are there? How many bases code for 1 amino acid? What is the main difference between DNA and mRNA State the location in the cell where amino acids are assembled into proteins Give an account of protein synthesis