Cell
the basic unit of structure and function in living things; basic unit of life; so small can only be seen with microscope
Tissues
groups of cells that work together to perform a function
Organs
tissues that work together to perform a function
Organ Systems
organs that work together to perform a function
Microscope
instrument that that uses lenses to magnify small object to make them look larger
Cell theory
scientific theory that states the following:
1. All organism are made of cells.
2.Cells are alive and the basic units of structure and function in all organisms.
3.All cells come from other cells.
DNA
genetic information; deoxyribonucleic acid
Prokatyotes
have prokaryotic cells and are single-celled (unicellular)
Organelle
different parts of a cell; "small organs
Eukaryotes
have eukaryotic cells
Cytoplasm
clear, thick gel like fluid that holds the organelles
Cell Wall
a rigid layer of nonliving material that surrounds plant cells only; is made primarily of cellulose
cell membrane
a cell structure that controls which substances can enter or leave the cell; found in both plant and animal cells
nucleus
the cell's control center; surrounded by the nuclear envelope; contains chromatin, which have all the instruction for cell's functions; contains the nucleolus, where the ribosomes are made
mitochondria
rod-shaped; they change energy in food to energy the cell can use to carry out its functions; cell's "powerhouse
Endoplasmic Reticulum (ER)
forms a maze of passageways in which materials are carried from one part of the cell to the other
Ribosomes
a small grain-like structure in the cytoplasm where proteins are made
Golgi Bodies
receives proteins and other newly formed materials from the ER, packages them, and sends them to other parts of the cell or outside of cell; look like flattened sacks
Chloroplasts
only in plant cells; captures energy from sunlight and uses it to produce food
Vacuoles
storage area; plants usually only have one large one; animal cells may not have one
Lysosome
cell's clean up crew; small and round, contain chemicals that break down certain materials in the cell
Cell division
process in which a parent cell divides to produce daughter cells
cell cycle
phases that a cell goes through from one cell division to the next; life cycle of a eukaryotic cell
Mitosis
division of the nucleus; produces 2 daughter cells that are genetically identical to parent
Meiosis
division of a cell that results in four daughter cells that contain half the amount of DNA than the parent cells; important for creating offspring
Interphase
stage of the cell cycle where the cell grows, make DNA and prepares to divide; has three stages to it: G1, S, and G2
DNA replication
DNA makes an identical copy of itself
Cancer
disease that occurs when the cell cycle is not regulated and cells divide out of control, causing a tumor to form
chromosomes
a doubled rod of condensed chromatin; contains DNA that carries genetic information; has two rods because the cell's DNA has replicated and each rod is an exact copy of the other; each rod is called a chromatid and they are held together by a centromere
Sister chromatids
2 identical copies of a chromosome
Centromere
area of chromosome where sister chromatids are held together
Cytokinesis
cell movement
Gametes
reproductive cells like sperm or eggs; have half the number of chromosomes as parent cell
Sexual reproduction
combining of gametes from two parents
Zygote
Cell that forms when a sperm and egg unite; the first cell of a new organism.
homologous chromosome
pair of chromosomes that have the same size and shape and contain the same genes but different alleles; are similar but NOT identical
Allele
different forms of genes on a chromosome
Haploid
Having one set of chromosomes, as in sperm and egg; n.
Diploid
Having two sets of chromosomes; 2n
Crossing over
exchange of DNA between homologous chromosomes; only happens in prophase I of meiosis