Ch. 3: Structure and Function of Cells

Why are almost all cells microscopic?

to improve efficiency (maximizes exterior surface area)

2 major events of endosymbiotic theory

1) infolding of cell membrane to make organelles

2) engulfing of other cells that became organelles

what does the endosymbiotic theory explain?

how prokaryotes evolved into eukraryotes

what are the two most common molecules in the cell membrane?

phospholipids and proteins

why is the cell membrane called selectively permeable?

it determines what goes in and out of the cell

what type of transport moves molecules against the gradient and requires ATP?

active transport

which direction do molecules move during active transport?

low concentration to high concentration

which direction do molecules move during diffusion?

high concentration to low concentration?

what is it called when a cell needs to move large molecules into the cell?

endocytosis

what is it called when a cell needs to move large molecules out of the cell?

exocytosis

when are endocytosis and exocytosis useful?

when a cell needs to move large items or many molecules across the membrane

what is housed in the nucleus of a eukaryotic cell?

DNA

cells that are the most active have the most…

mitochondrion

what organelle is involved in cellular respiration?

mitochondrion

what is the function of the rough endoplasmic reticulum? why is it called the rough endoplasmic reticulum?

makes proteins, dotted with ribosomes,

what organelle supports the theory of endosymbiosis? why?

mitochondrion has prokaryotic-like DNA and its own ribosomes. it might have been a prokaryotic cell that was engulfed

what does the golgi apparatus do?

refines, packages, and ships macromolecular products

what does the smooth endoplasmic reticulum do?

makes lipids

what is the cytoskeleton? what is its function?

protein scaffolding inside of the cell that gives cell structure, helps move things around the cell, helps with cell division

what do lysosomes do?

digests damaged organelles and cellular debris, intracellular digestion

what is the function of mitochondria?

energy production (ATP)

what is the function of the plasma membrane?

defines boundary of cell, controls entrance and exit of things into/out of cell

what is a codon?

a 3 letter sequence that codes for a specific amino acid

what is the start codon?

AUG

what happens if the start codon is not on a piece of RNA?

the RNA will not be made into a protein