B1-Cell Biology

prokaryotic vs eukaryotic

1- NUCLEUS - prokaryotic has no nucleus, dna floats in cytoplasm in loops or in plasmids and eukaryotic has a nucleus with its dna enclosed in it

2- SIZE - prokaryotic smaller, eukaryotic bigger

3- ORGANELLES - prokaryotic has no membrane bound organelles and eukaryotic has organelles

what is a unicellular organism

single cell capable of carrying out all life processes independently

what additional organelles are in a plant cell?

cell wall, chloroplast, permanent vacuole

what is the function of a chloroplast?

site of photosynthesis, contains green pigment called chlorophyll

what is the function of a nucleus

contains genetic material, controls the cell

what is the function of the mitochondria

site of aerobic respiration

what is the function of the cell membrane

controls what substances go in and out of the cell

what is the function of the cytoplasm

site of chemical reactions

what is the function of the permanent vacuole

Filled with cell sap, providing structural support

what is the function of the cell wall

made of cellulose, provides support

how are red blood cells adapted to their function

1 - They have no nucleus to allow more space for haemoglobin, to

carry more oxygen.

2 - They have a circular biconcave shape which

allows them to squeeze through narrow blood vessels

how is a root hair cell adapted for its function

large surface area for increased rate of osmosis and or a active transport

how is a sperm cell adapted for its function

lots of mitochondria for energy to swim

how is a muscle cell adapted for its function

lots of mitochondria for energy for movement

what is xylem

transports water and minerals in plants

what is phloem

transports dissolved sugars in plants

what is stem cells

an undifferentiated cell

describe how you would make a microscope slide

1.Place a thin layer of the sample on a slide

2.Add one drop of dye (e.g. iodine)

3.Slowly, lower down a cover slip

what are the advantages of an electron microscope compared to a light microscope

higher magnification and resolving power - can study cells in finer detail

what is resolution

the smallesr change in the quantity being measured of measurement instrument that gives a perciptible change in the reading

which magnification should you start with on a microscope

lowest

equation for total magnification

eyepiece lens magnification X Objective lens magnification

what is diffusion

the spreading out of the particles of any substance in a solution or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration

what factors affect the rate of diffusion

1. the difference in concentrations (concentration gradient)

2. the temperature

3. the surface area of the membrane.

what is osmosis

the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane

what is active transport

moves subatances from a more dilute solution to a more concentrated solution against a concentration gradient. this requires energy from respiration

where is active transport used

1. mineral ions to be absorbed into plant root hairs from

very dilute solutions in the soil.

2. It also allows sugar molecules to be absorbed from

lower concentrations in the gut into the blood which has

a higher sugar concentration