B1: cell biology Flashcards
Nucleus
In animal and plant cell
Contains genetic material that controls the activities of the cell
Cytoplasm
In animal and plant cell
Gel- like substance where most chemical reactions happen
Contains enzymes that control these chemical reactions
Cell membrane
In animal and plant cell
Holds the cell together and controls what goes in and out
Mitochondria
In animal and plant cells
Where most of the reactions for aerobic respiration take place
Ribosomes
In animal and plant cells
Where proteins are made in the cell
Cell wall
Plant only
Made of cellulose
Supports the cell and strengths it
Vacuole
Plant only
Contains cell sap a weak diluting of sugar and salts
Chloroplasts
Plant only
Photosynthesis occurs, which makes food for the plant
Contains a green substance called chlorophyll which absorbs the light needed for photosynthesis
Bacterial cells
Much smaller
Have cell membranes, cell wall , cytoplasm
Don’t have chloroplasts or mitochondria , don’t have a true nucleus instead they have a singular strand of DNA that floats freely in the cytoplasm
They contain one or more small rings of DNA called plasmids
Formula for magnification
Magnification = image size/ real size
Formula for image size
Image size = magnification * real size
Formula for real size
Real size = image size / magnification
How to prepare a slide to view a onion cell
- Add a drop of water to the middle of a clean slide
- cut up an onion and separate it out into layers . Use tweezers to peel off some epidermal tissue from the bottom of the layers
- Using the tweezers place the epidermal tissue into the water in the slide
- Add a drop of iodine solution (stains are used to highlight objects in a cell by adding colour)
- Place a cover slip on top - make sure there are no bubbles as they will obstruct your view of the specimen
Differentiation in cells
Differentiation is the process by which a cell changes to become specialised for its Job
Function of Sperm cells specialised cells)
Specialised for reproduction
Function:
- is to get male DNA to the female DNA
Structure of sperm cell (specialised cell)
Has a long tail and a streamlined head to help it swim to the egg
A lot of mitochondria in the cell to provide the energy needed
Carried enzymes in its head to digest through the egg cell membrane
Function of Nerve cells ( specialised cells)
Specialised for rapid signalling
function:
-To carry electrical signals from one part of the body to another
Structure of the nerve cell ( specialised cells)
Long to cover more distance and have branched connections at their ends to connect to another nerve cells and form a network throughout the body
Function of the muscle cells (specialised cell)
Specialised for contraction
Function:
- is to contract quickly
Structure of muscle cells ( specialised for contraction)
Long so they have space to contract
contain lots of mitochondria to generate the energy needed for contraction