cells Flashcards
microscope
an instrument for viewing small objects
cells
the smallest unit of life. Cells are the building blocks of living things.
light microscopes
instrument for viewing very small objects. A light microscope can magnify things up to 1500 times.
light microscopes
instrument for viewing very small objects. A light microscope can magnify things up to 1500 times.
electron microscopes
instrument for viewing very small objects. An electron microscope is much more powerful than a light microscope and can magnify things up to a million times.
monocular
describes a microscope through which the specimen is seen using one eye only
binocular
a microscope with two eyepieces, so you use both eyes to look at the object
stereo
describes a microscope through which the specimen is viewed using both eyes
magnification
the number of times the image of an object has been enlarged using a lens or lens system. For example, a magnification of two means the object has been enlarged to twice its actual size.
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
nanotechnology
a rapidly developing field that includes studying and investigating cells and other objects of the smallest dimensions
Prokaryotes
organism classified as belonging to the Prokaryotae kingdom
eukaryote
member of the group of organisms that has a membrane around the nucleus in each of their cells
binary fission
reproduction by the division of an organism (usually a single cell) into two new organisms
Animalia
the kingdom of organisms that have cells with a membrane around the nucleus, but no cell wall, large vacuole or chloroplasts
plantae
the kingdom of organisms that have cells with a membrane around the nucleus, cell wall, large vacuole and chloroplasts, commonly called plants
fungi
the kingdom of organisms, such as mushrooms and moulds, that help to decompose dead or decaying matter
Protoctista
the kingdom of organisms, including algae and protozoans, that do not fit into other groups
Prokaryotae
the kingdom of organisms that consist of single cells with a nucleus not surrounded by a membrane or a cell wall, commonly called bacteria
mitochondria
small rod-shaped organelles that supply energy to other parts of the cell. They are usually too small to be seen with light microscopes. Singular = mitochondrion.
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.
cellular respiration
the chemical reaction involving oxygen that moves the energy in glucose into the compound ATP. The body is able to use the energy contained in ATP.
cellular respiration
the chemical reaction involving oxygen that moves the energy in glucose into the compound ATP. The body is able to use the energy contained in ATP.
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.
chlorophyll
the green-coloured chemical in plants that absorbs the light energy used in photosynthesis to make food from carbon dioxide and water
nucleus
central part of an atom, made up of protons and neutrons. Also roundish structure inside a cell that acts as the control centre for the cell. Plural = nuclei.
chromosomes
tiny, thread-like structure inside the nucleus of a cell. Chromosomes contain the DNA that carries genetic information.
deoxyribonucleic acid (DNA)
the chemical substance found in all living things that encodes the genetic information of an organism
mitosis
cell division process that results in new cells with the same number of chromosomes as the original cell
clones
identical copy
cytokinesis
the process where the cytoplasm of a cell divides to form two daughter cells
infectious diseases
disease that can be transferred from one organism to another
infectious diseases
disease that can be transferred from one organism to another
non-infectious diseases
disease that cannot be transferred from one organism to another
antibiotics
substance derived from a micro-organism and used to kill bacteria in the body
disinfectants
chemical used to kill bacteria on surfaces and non-living objects
antiseptics
mild disinfectant used on body tissue to kill microbes
bactericidal
describes an antiseptic that kills bacteria
bacteriostatic
describes an antiseptic that stops bacteria from growing or dividing but doesn’t kill them
phloem
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
xylem vessels
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.
lignin
a hard substance in the walls of dead xylem cells that make up the tubes carrying water up plant stems. Lignin forms up to 30 per cent of the wood of trees.
stomata
small openings mainly on the lower surface of leaves. These pores are opened and closed by guard cells. Singular = stoma.
transpiration stream
movement of water through a plant as a result of loss of water from the leaves
vascular bundles
groups of xylem and phloem vessels within plant stems
transpiration
loss of water from plant leaves through their stomata
guard cells
cells on either side of a stoma that work together to control the opening and closing of the stoma
guard cells
cells on either side of a stoma that work together to control the opening and closing of the stoma
wilt
droop. Plant stems and leaves wilt when there is insufficient water in their cells.
vacuoles
sacs within a cell used to store food and wastes. Plant cells usually have one large vacuole. Animal cells have several small vacuoles or none at all.
flaccid
describes cells that are not firm due to loss of water
turgid
describes something that is firm
epidermis
outermost layer of the skin
dermis
the medical name for the deeper part of the skin
receptors
special cells that detect energy and convert it to electrical energy that is sent to the brain
sweat glands
tiny, coiled tube in the skin through which water and salt are removed from the body, helping to control body temperature
pores
small opening in the skin. Perspiration reaches the surface of the skin through pores.
evaporates
change state from a liquid to a gas. Evaporation occurs only from the surface of a liquid.
cancer
a disease resulting in the uncontrolled growth of body cells, forming tumours
tumour
an abnormal growth
benign
describes a tumour that does not spread to other parts of the body
malignant
describes a type of tumour that damages cells and can spread to other parts of the body
