B1 CELL BIOLOGY Flashcards
What is an eukaryotic cell?
A cell with no nucleus e.g plants and animal cells
what is a prokaryotic cell
A cell that has no nucleus e.g bacteria and genetic material is not enclosed in the nucleus
What is a light microscope
Light microscope use light and lenses to form an image of a specimen and magnify it. They let us see individual cells and structures e.g. nuclei
What is an electron microscope
Electron microscopes use electrons instead of light to form an image
Give 3 advantages of an electron microscope
1)Higher magnification
2)Higher resolution
3)See much more detail e.g. internal structures of mitochondria
FORMULA FOR MAGINFICATION
MAGINIFICATION=IMAGE SIZE/REAL SIZE
FORMULA FOR MAGINFICATION
MAGINIFICATION=IMAGE SIZE/REAL SIZE
How do you prepare a microscope slide?
1)Add a drop of water to the middle of a clean slide
2)Use tweezers to pull off epidermal tissue on an onion
3)Use tweezers to place epidermal tissue into water on the slide
4)Add a drop of iodine solution to stain
5)Place a cover slip on top and make sure not to get any air bubbles inside
How do you prepare a microscope slide?
1)Add a drop of water to the middle of a clean slide
2)Use tweezers to pull off epidermal tissue on an onion
3)Use tweezers to place epidermal tissue into water on the slide
4)Add a drop of iodine solution to stain
5)Place a cover slip on top and make sure not to get any air bubbles inside
How do you use a light microscope?
1)Clip the slide onto the stage
2)Select the lowest powered objective lens
3)Use the coarse adjustments knob to move stage up
4)Look down the eye piece and use course adjustment knob to move the stage downwards until the image is roughly in focus
5)Adjust fine focus to get a clear image
6)Swap to a higher powered objective lens for greater magnification
WHAT IS DIFFERENTIATION
the process by which a cell changes to become specialised for its job and allows them to carry out a specific function
WHEN DO ANIMAL CELLS DIFFERENTIATE
at an early stage
How long do plant cells differentiate for
Many types of plant cells retain the ability to differentiate throughout life
What is a sperm cell and its features
To get male DNA to the female DNA
1) long tail and streamlines head to help swim to the egg
2) mitochondria in the cell to provide energy needed
3) carries enzymes in the head to digest through the egg cell membrane
WHAT ARE NERVE CELLS AND ITS FEATURES
to carry electrical signals from one part of the body to another
1) Cells are long to cover more distance
2) Have branches to connect to other nerve cells and form a network across the body
WHAT ARE MUSCLE CELLS AND ITS FEATURES
to contract more quickly
1) cells are long so that there are more space to contract
2)contain lots of mitochondria to generate energy needed for contraction
WHAT ARE ROOT HAIR CELLS AND ITS FEATURES
to absorb water and minerals
1) Long hairs which give a large surface area for absorbing water and mineral ions from the soil
WHAT ARE PHLOEM AND XYLEM CELLS AND THEIR FEATURES?
Both transport food and water around plants
1) cells are long and joined end to end to form the tubes
2)Xylem cells are hollow in the center
3)Phloem have very subcellular structures so that stuff can flow through them