Biology AL

• The nucleus contains the genetic material (DNA) that controls all cellular activities.
• The field of view when looking down a microscope is represented by a circle aligned with the stage micrometer.
• The bottom scale on the stage micrometer is aligned against the eyepiece graticule, which is already within the eyepiece of the microscope.
• To align the stage micrometer, count how many divisions on the eyepiece graticule fit into one of the divisions on the stage micrometer.
• Each division on the stage micrometer is worth 10 micrometers, as indicated by the value '10' on the stage micrometer.
• One division on the eyepiece graticule is worth 10 micrometers, allowing the size of the specimen to be calculated.
• The magnification is calculated by dividing the size of the image by the size of the real object.
• Staining is used to make cell components more obvious under the microscope.
• Differential staining involves using multiple chemical stains to stain different parts of the cells different colors.
• Gram staining involves using two different stains to identify what type of bacteria is present.
• Scientific drawings are different from artistic drawings, with specific rules and guidelines.
• Scientific drawings should include a title, magnification, and annotation of the cell components or cells themselves that are visible.
• Scientific drawings should be done using a sharp pencil, with no gaps or overlapping lines, and should not include any coloring or shading.
• The aim of scientific drawings is to show the size, location, proportion, and labeling of cell components.
• There are four different types of microscopes: light or Optical microscopes, transmission electron microscopes, scanning electron microscopes, and laser scanning confocal microscopes.
• During metaphase one, homologous pairs of chromosomes line up opposite each other on either side of the equator, but it is random for each homologous pair which side the maternal and the paternal chromosomes align.
• Independent assortment increases the genetic diversity and happens during metaphase one.
• There are 23 homologous pairs in humans, which means there would be two to the power of 23 possible combinations of how those homologous pairs could align.
• Each gamete receives different combinations of the maternal and paternal chromosomes.
• Multicellular organisms are organized in the following way: cells are the smallest structure, then tissues, organs, organ systems, and the entire organism.
• Specialized cells include: heart, brain, liver, kidney, and blood.
• Stem cells are undifferentiated cells that can self-renew, meaning they can continually divide and become specialized different types of stem cells have different differentiation abilities.
• Totipotent cells can divide and produce any type of body cell during development.
• Katipotent cells occur only for a limited time in early mammalian embryos and develop into very patent stem cells.
• Multi-potent cells such as the ones found in bone marrow can differentiate into a limited number of cells.
• Unipotent cells can only differentiate into one other type of cell.
• Potential uses of stem cells include repairing damaged tissues and treating neurological conditions such as Alzheimer's and Parkinson's.
• Stem cells can also be used for research into developmental biology.
• Resolution in microscopy is the minimum distance between two objects in which you can still view them as separate.
• Magnification in microscopy refers to how many times larger the images compared to the actual object that you are viewing.
• The rate of reaction in an enzyme-controlled reaction increases with the addition of unlimited substrate, but when a certain amount of substrate is added, the rate of reaction plateaus due to insufficient substrate binding to the large number of enzymes.
• Competitive inhibitors bind to the active site of an enzyme, preventing the substrate from binding and lowering the rate of reaction.
• Most competitive inhibitors are reversible, meaning they can be removed from the enzyme.
• Non-competitive inhibitors bind to the enzyme at a position other than the active site, changing the shape of the active site and preventing the substrate from binding.
• End product inhibitors are inhibitors where the product of the reaction is a reversible inhibitor for the enzymes involved in controlling that reaction.
• Some enzyme-controlled reactions require an additional non-protein molecule such as a coenzyme cofactor or a prosthetic group to catalyze the reaction.
• Coenzymes are organic molecules and cofactors are inorganic molecules.
• A prosthetic group on an enzyme is a type of cofactor but they differ in that they are permanently attached to the enzyme.
• Biocovalent or non-covalent Force precursor activation is when enzymes often occur in an inactive form and they require to be activated by a cofactor so that they can actually work.
• An enzyme is activated by The Binding of a cofactor as this causes a change in the shape for the tertiary structure so that the act of sight now becomes complementary enough in shape to its substrate for it to bind.