SB1 Flashcards
How do you work out a microscopes magnification?
Eyepiece lens * objective lens
Resolution
The smallest distance between two points that can still be seen as two points
Electron microscopes?
Before 1930s. Shoot beams of electrons. these microscopes can magnify up to x2 000 000.
What is a eukaryotic cell
A cell with a nucleus
Cell membrane
A very thing bag. Controls what enters and leaves and separates one cell from another.
Cytoplasm
Contains a watery jelly and is where most of the cell’s activity take place.
Mitochondria
Jelly bean shaped structures in which aerobic respiration takes place.
Ribosomes
These make protein for a cell.
Nucleus
Controls the cell and its activity. Contains chromosomes which contain DNA.
Specialized cells
They have a specific job. There are about 200 types of specialized cells in humans. All human cells have the same basic design but their sizes, shapes and sub-cellular structures are different so that they are adapted to their functions.
What is a gamete
A specialized sexual reproduction cell that fuses with another gamete to develop and embryo.
Haploid cells
A cell with one copy of each chromosome
Diploid cells
Cells with two sets of chromosomes.
Acrosome
The tip of the head of a sperm cell. It contains enzymes that break down the substances in the egg cell’s jelly coat.
Flagellum
A tail which enables the cell to swim
Prokaryotic cells
Do not have nuclei or chromosomes
Amylase
Is found in saliva and the small intestine. It is to break down starch and small sugars (e.g maltose)
Catalase
Found in most cells but especially liver cells. Breaks down hydrogen peroxide made in many cell reactions to water and oxygen.
Biological catalyst
Speeds up rates of reaction (e.g breakdown of cells like digestion)
Chemical reagents
Used in food tests to identify breakdown of cells
Iodine
Changes from a yellow-orange colour to a blue-black colour when in contact with starch
Benedicts solution
Mixed with food solution and placed in a hot water bath for a few minutes. No colour change = no reducing sugar, slight colour change = little reducing suga, orange = more reducing sugar, red = lots of reducing sugar.
Active site
Where the substrate of the enzyme fits at the start of the reaction. Every enzyme can only work with a specific substrate.
Changes in pH or temperature
Can affect the shape of the active site. This can cause the enzyme to no longer fit in it.
Enzyme denature
When the active site is disfigured to the point where a substrate cant bind to it.
Optimum temperature/pH
The temperature. pH at which an enzyme works the fastest.
Diffusion
The movement of particles from an area of high concentration to an area of low concentration.
Concentration gradient.
The difference between two concentrations forms a concentration gradient. The bigger the difference, the steeper the concentration and the faster diffusion occurs.
Osmosis
The diffusion of small molecules (e.g water) through a semi-permeable membrane. Osmosis can cause tissues to gain or lose mass.
Change in mass
final mass-initial mass/ initial mass *100
Active transport
Cells transporting molecules against a concentration gradient. This is an active process so requires energy to carry out.
