cells Flashcards
microscope
an instrument for viewing small objects
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.
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
prokaryotic
organism classified as belonging to the Prokaryotae kingdom
eukaryotic
member of the group of organisms that has a membrane around the nucleus in each of their cells
cell membrane
structure that encloses the contents of a cell and allows the movement of some materials in and out
cytoplasm
the jelly-like material inside a cell. It contains many organelles such as the nucleus and vacuoles.
nucleus
the central and most important part of an object, movement, or group, forming the basis for its activity and growth.
robosome
small structures within a cell in which proteins such as enzymes are made
mitochodria
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.
chloroplast
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.
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
stomata
small openings mainly on the lower surface of leaves. These pores are opened and closed by guard cells. Singular = stoma.
skin
describes a tumour that does not spread to other parts of the body
tumor
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
cell wall
protects the cell
vacuole
a space or vesicle within the cytoplasm of a cell
guard cell
each of a pair of curved cells that surround a stoma
xylem cell
plant vascular tissue that conveys water and dissolved minerals from the roots
phloem cell
issues in plants that conduct foods made in the leaves to all other parts of the plant
leaf cell
any cell found in a leaf
epidermal cell
hat is a precursor of a melanocyte
root hair cell
a hair forming cell on the epidermis of a plant
mitosis
a type of cell division that results in two daughter cells each having the same number
DNA
deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms
chromosomes
a threadlike structure of nucleic acids
cytokinesis
he cytoplasmic division of a cell at the end of mitosis or meiosis
binary fission
is the division of a single entity into two or more parts
independent variable
a variable whose variation does not depend on that of another
dependent variable
a variable whose value depends on that of another
controlled variable
a variable which is constant and unchanged throughout the course of the investigation
