35 terms

PS2: Cell Biology Key Terms

Key terms from our Cells and Genes unit.
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nucleus
where DNA is stored in the cell
nucleolus
a compartment in the nucleus where ribosomes are made
cytoplasm
the goo that fills the cell and contains all the other organelles
cell membrane
the outer covering of the cell; controls what enters and exits the cell
cytoskeleton
a network of fibers that gives the cell its shape and allows molecules to move around inside the cell
lysosome
the organelle that breaks things down so that their parts can be reused by the cell
mitochondria
the organelle that converts food into usable energy
golgi body
where particles produced by the cell are packaged for distribution
ribosome
the organelle that puts proteins together
rough endoplasmic reticulum
a maze in the cell lined with ribosomes; where proteins are produced
smooth endoplasmic reticulum
a maze in the cell where fats (or lipids) are produced
vacuole
a storage container in the cell; often contains water, nutrients, or wastes
chloroplast
the organelle where photosynthesis, which converts sunlight into sugar (food), takes place
cell wall
the tough outer covering of plant cells that helps them stand up straight
cilia
the tiny hair-like structures that stick out from the surface of a cell to help it move
flagellum
a whip-like tail that helps a cell move
pseudopod
the fake foot some cells make to help them move and/or eat
active transport
when things go through a cell membrane using energy from the cell; proceeds against the concentration gradient
passive transport
when things go through a cell membrane using no energy; proceeds down the concentration gradient
diffusion
when small molecules pass directly through the cell membrane; a form of passive transport
protein channel diffusion
when larger molecules pass through the cell membrane using a protein that acts as a tunnel; a form of passive transport
osmosis
when water passes through the cell membrane; a form of passive transport
endocytosis
when the cell membrane forms a pocket around what it wants to ingest and engulfs it (pacman style)
exocytosis
a vacuole that releases molecules from inside the cell
hypertonic
when the concentration of a substance is higher outside a cell; causes the cell to shrink
hypotonic
when the concentration of a substance is lower outside a cell; causes the cell to swell up
isotonic
when the concentration of a substance is the same inside and outside a cell; the cell's size does not change
gene
a stretch of DNA that codes for a single trait
alleles
different versions of the same gene
homozygous
when an organism has two copies of the same allele; represented with two letters that are the same size
heterozygous
when an organism has two different alleles; represented with one capital letter and one lowercase letter
phenotype
an organism's physical trait; how it looks PHYSICALLY
genotype
an organism's combination of alleles; its GENES
prokaryotic
primitive cells with no nucleus or organelles with membranes
eukaryotic
more advanced cells that have a nucleus and many organelles with membranes