KEY CONCEPTS IN BIOLOGY Flashcards
(23 cards)
What is the difference between an electron microscope and a light microscope?
A light microscope is designed for more regular use. It has a lower magnification and resolution but can be used for living cells. They use beams of light.
An electron microscope has a higher magnification and resolution but cannot be used on living cells. They use a beam of electrons. Electron microscopes are better at viewing sub cellular structures.
What is the method used when preparing a microscope slide to view an onion sample?
- Place a single drop of water onto a slide
- Peel some onion skin and apply it to the drop of water. Ensure it is flat with no air bubbles.
- Stain cells with iodine
4.Place a coverslip over it. - Place a drop of stain next to the coverslip and draw it under the slip with filter paper.
List the animal cell subcellular structures
Cytoplasm
Nucleus
Ribosome
Mitochondrion
Cell membrane
List the plant cell subcellular structures
All animal cell structures, as well as
Cell wall
Permanent vacuole
Chloroplasts.
List the bacterial cell subcellular structures
Cell membrane
Cell wall
Plasmid DNA
Chromosomal DNA
Flagellum (sometimes)
Animal specialised cellls:
Gametes (Sperm and Egg)
Ciliated Epithelial cell
Plant specialised cells:
Root hair cell
Palisade cell
Xylem and Phloem cells
What is resolution in terms of Microscopy?
The ability of a Microscope to distinguish details of a specimen or sample.
Why can’t a light microscope see certain subcellular structures?
Due to limits of resolution and size.
How do you find total magnification?
Take the magnification of the current objective lens and multiply it by the eyepiece.
E.g. 10x40 = 400micrometers
How do you find magnification using a real object?
Magnification = Size of image / size of real object
What is the difference between Animal and Plant cells?
Animal Cells lack a cell wall, permanent vacuole and chloroplasts.
What is visible on an animal cell through a LIGHT MICROSCOPE?
Membrane, Cytoplasm, Nucleus
What is visible on a plant cell through a LIGHT MICROSCOPE?
Cytoplasm, Nucleus, Vacuole, Membrane, Wall, Chloroplast
What is the function of the Ribosomes in a cell?
The Ribosomes are the centre of a process called ‘protein-synthesis’ where proteins are created for a cell.
What is the function of the Mitochondria?
The mitochondria are where aerobic respiration takes place in a eukaryotic cell, releasing energy inside the mitochondria.
What is the function of the nucleus?
The nucleus houses all genetic information and serves as a control centre for cells.
What is the function of the cell membrane?
The cell membrane regulates the transportation of materials entering and exiting the cell.
What is the function of the cell wall?
Strengthens the cell and supports the plant.
What is the function of Chloroplasts?
Absorbs light energy for photosynthesis, as well as containing enzymes used for photosynthesis.
How is a sperm cell adapted to its function?
The head contains genetic material for fertilisation inside a HAPLOID nucleus.
The acrosome in the head contains enzymes that allow the sperm to penetrate the egg.
The middle piece has many mitochondria for energy.
The cell also has a flagellum to propel itself.
How is an egg cell adapted to its function?
Cytoplasm contains nutrients for the growth of the early embryo.
HAPLOID nucleus contains genetic material for fertilisation.
Cell membrane changes after 1 sperm enters so no more can enter.
What are enzymes?
Proteins that function as biological catalstys.
