Define a prokaryotic cell?
Cell lacking membrane bound organelles with circular DNA and plasmids.
Give four structures found in prokaryotes but not eukaryotes?
Circular DNA. Plasmids. 70S ribosomes. Cell wall of murein.
Define magnification?
How many times larger an image is compared to the actual object.
Define resolution?
The ability to distinguish two points as separate.
Equation for magnification?
Magnification = image size ÷ actual size.
Describe prophase in mitosis?
Chromosomes condense. Nuclear envelope breaks down. Spindle fibres form.
Describe metaphase in mitosis?
Chromosomes line up at the equator attached to spindle fibres by centromeres.
Describe anaphase in mitosis?
Sister chromatids separate and are pulled to opposite poles by spindle fibres.
Describe telophase in mitosis?
Chromatids reach poles. Nuclear envelope reforms. Chromosomes decondense.
Describe cytokinesis?
Division of the cytoplasm forming two identical daughter cells.
What is the role of mitosis?
Growth. Repair. Asexual reproduction. Maintaining chromosome number.
How does cancer relate to mitosis?
Cancer is uncontrolled cell division due to mutations in genes controlling the cell cycle.
Describe the structure of a cell membrane?
Phospholipid bilayer with proteins cholesterol and carbohydrates.
Explain the role of the phospholipid bilayer?
Forms a selective barrier controlling entry and exit of substances.
Explain the role of membrane proteins?
Transport molecules. Act as receptors. Provide structural support.
