Cell Biology Flashcards
(46 cards)
What do microscopes do?
Magnify the image of a biological specimen so that it appears larger.
Name the 9 parts of a microscope
Eyepiece, coarse focus, fine focus, objective lenses, stage clip, condenser, arm, stage, mirror
What is the formula to calculate magnification?
Magnification=size of image(image size)/real size of image(actual size)
The ability to see greater detail in an image depends on the r…?
Resolution or resolving power
What does the electron microscope use instead of light rays?
Electron microscopes use a beam of electrons instead of light rays.
What are the two types of electron microscopes?
The scanning electron microscope (SEM) and the transmission electron microscope (TEM).
What does the scanning electron microscope examine?
The SEM has a large field view so can be used to examine the surface structure of specimens. SEMS are often used at lower magnifications.
What does the transmission electron microscope examine?
The TEM is used to examine thin slices or sections of cells or tissues.
What is the function of the nucleus?
Contains generic material, including DNA, which controls the cell’s activities.
What is the function of cytoplasm?
A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It is where many of the chemical reactions happen.
What is the function of cell membrane?
It’s structure is permeable to some substances but not to others. It therefore controls the movement of substances in and out of the cell.
What is the function of mitochondria?
Organelles that contain the enzymes for respiration, and where most energy is released in respiration.
What is the function of ribosomes?
Tiny structures where protein synthesis occurs.
What the difference between plant and animal cells?
Plant cells have a permanent vacuole and a cell wall and chloroplasts, animal cells don’t.
What is the function chloroplasts?
Organelles that contains the green pigment, chlorophyll, which absorbs light energy for photosynthesis. Contains the enzymes needed for photosynthesis.
What is the function of the cell wall?
Made from cellulose fibres and strengthens the cell and supports the plant.
What is the function of a permanent vacuole?
Filled with cell sap to help keep the cell turgid.
What cells are prokaryotic cells?
Cells of bacteria are called prokaryotic cells.
What are cells of eukaryotic cells?
Cells of animals, plants and fungi are called eukaryotic cells.
What type of cell division do eukaryotic cells use?
Mitosis
What type of cell division do prokaryotic cells use?
Binary fission
How is a sperm cell specialised for its role?
The head of the sperm contains the genetic material for fertilisation. The acrosome in the head contains enzymes so that the sperm can penetrate an egg. The middle piece is packed with mitrochondria to release energy needed to swim and fertilise the egg. The tail enables the sperm to swim.
How is the nerve cell specialised for its role?
The nerve cell is extended, so that the nerves can run to and from different parts of the body to the central nervous system. The cell has extensions and branches, so that it can communicate with other nerve cells, muscles and glands. The nerve cell is covered with a fatty sheath, which insulates the nerve cell and speeds up the nerve impulse.
How are muscle cells specialised for their role?
Muscle cells contain filaments of protein that slides over each other to cause muscle contraction. The arrangement of these filaments causes the banded appearance of heart muscle and skeletal muscle. They contain many well-developed mitochondria to provide the energy for muscle contraction. In skeletal muscle, the cells merge so that the muscle fibres contract in unison.
