Chapter 3-Cells Flashcards
Cell
the smallest unit of life. Cells are the building blocks of living things. There are many different sized and shaped cells in animals and plants, as well as single-celled organisms.
Light Microscope
instrument for viewing very small objects. A light microscope can magnify things up to 1500 times.
Scanning Electron Microscope
an electron microscope in which the surface of a specimen is scanned by a beam of electrons that are reflected to form an image.
Unicellular
describes an organism having only one cell
Multicellular
having many cells. Most plants and animals are multicellular.
Micrometre
a length of one millionth of a metre
Nanometre
a unit of measurement equal to one billionth of a metre
Eukaryotes
member of the group of organisms that has a membrane around the nucleus in each of their cells
Prokaryotes
organism classified as belonging to the Prokaryotae kingdom, the kingdom of organisms that consist of single cells with a nucleus not surrounded by a membrane or a cell wall, commonly called bacteria
Cell Membrane
structure that encloses the contents of a cell and allows the movement of some materials in and out
Nucleus
roundish structure inside a cell that acts as the control centre for the cell. Plural = nuclei.
Cytosol
the fluid found inside cells
Ribosomes
small structures within a cell in which proteins such as enzymes are made
Cytoplasm
the jelly-like material inside a cell. It contains many organelles such as the nucleus and vacuoles.
Chloroplasts
oval-shaped organelle found only in plant cells. Chloroplasts contain the pigment chlorophyll. They are the ‘factories’ in which carbon dioxide and water are changed by sunlight and water into food by the process of photosynthesis.
Chlorophyll
the green-coloured chemical in plants that absorbs the light energy used in photosynthesis to make food from carbon dioxide and water
Photosynthesis
the food-making process in plants that takes place in chloroplasts within cells. The process uses carbon dioxide, water and energy from the sun.
Guard Cells
cells on either side of a stoma that work together to control the opening and closing of the stoma
Stomata
small openings mainly on the lower surface of leaves. These pores are opened and closed by guard cells. Singular = stoma.
Xylem Cells
pipelines for the flow of water up plants. They are made up of the remains of dead xylem cells fitted end to end with the joining walls broken down. Lignin in the cell walls gives them strength.
Phloem Cells
Cells that make up a type of tissue that transports sugars made in the leaves to other parts of a plant
Translocation
transport of materials, such as water and glucose, in plants
Mitosis
cell division process that results in new cells with the same number of chromosomes as the original cell
Chromosomes
tiny, thread-like structure inside the nucleus of a cell. Chromosomes contain the DNA that carries genetic information.
DNA
deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.
Cytokinesis
the process where the cytoplasm of a cell divides to form two daughter cells
Antiseptic
mild disinfectant used on body tissue to kill microbes
Disinfectant
chemical used to kill bacteria on surfaces and non-living objects
Antibiotics
substance derived from a micro-organism and used to kill bacteria in the body
Epidermis
outermost layer of the skin
