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Flashcards in Ch. 4 Deck (48)
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1

light microscope

LM

an optical instrument w/ lenses that refract (bend) visible light to magnify images & project them into a viewer's eye or onto photographic film

2

cell theory

the theory that all living things r composed of cells & that all cells come from other cells

3

electron microscope

EM

an instrument that focuses an electron beam through, or onto the surface of, a specimen

an electron microscope achieves a hundredfold greater resolution than a light microscope

4

scanning electron  microscope

SEM

a microscope that uses an electron beam to study the surface architecture of a cell or other specimen

5

transmission electron microscope

TEM

a microscope that uses an electron beam to study the internal structure of thinly sectioned specimens

6

prokaryotic cell

a type of cell lacking a membrane-enclosed nucleus & other membrane-enclosed organelles

found only in the domains Bacteria & Archaea

7

eukaryotic cell

a type of cell that has a membrane-enclosed nucleus & other membrane-enclosed organelles

all organisms except bacteria & archaea are composed of eukaryotic cells

8

plasma membrane

the membrane that sets a cell off from its surroundings & acts as selective barrier to the passage of ions & molecules into & out of the cell

consists of a phospholipid bilayer in which r embedded molecules of protein & cholesterol

9

chromosome

a threadlike, gene-carrying structure found in the nucleus of a eukaryotic cell & most visible during mitosis & meiosis

the main gene-carrying structure of a prokaryotic cell

consist of chromatin, a combo of DNA and protein

10

ribosome

a cell structure consisting of RNA and protein organized into 2 subunits & functioning as the site of protein synthesis in the cytoplasm

the ribosomal subunits r constructed in the nucleolus

11

cytoplasm

everything inside a cell b/w the plasma membrane & the nucleus

consists of a semifluid medium & organelles

12

nucleoid

a dense region of DNA in a prokaryotic cell

13

flagellum (flagella)

a long cellular appendage specialized for locomotion

the flagella of prokaryotes & eukaryotes differ in both structure & function - like cilia, eukaryotic flagella have a 9+2 arrangement of microtubules covered by the cell's plasma membrane

14

organelle

a membrane-enclosed structure w/ a specialized function w/in a cell

15

cellular metabolism

the chemical activities of cells

16

nucleus (nuclei)

the genetic control center of a eukaryotic cell

17

chromatin

the complex of DNA & proteins that constitutes eukaryotic chromosomes

often used to refer to the diffuse, very extended form taken by chromosomes when a cell isn't dividing

18

nuclear envelope

a double membrane, perforated w/ pores, which encloses the nucleus & separates it from the rest of the eukaryotic cell

19

nucleolus

a structure w/in the nucleus of a eukaryotic cell where ribosomal RNA is made & assembled w/ proteins imported from the cytoplasm to make ribosomal subunits

20

endomembrane system

a network of membranes inside & around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles

21

vesicle

a sac made of membrane in the cytoplasm of a eukaryotic cell

22

endoplasmic reticulum

ER

an extensive membranous network in a eukaryotic cell, continuous w/ the outer nuclear membrane & composed of ribosome-studded (rough) & ribosome-free (smooth) regions

23

smooth endoplasmic reticulum

SER

a network of interconnected membranous tubulues in a eukaryotic cell's cytoplasm

lacks ribosomes

24

rough endoplasmic reticulum

RER

a network of interconnected membranous sacs in a eukaryotic cell's cytoplasm

membranes r studded w/ ribosomes that make membrane proteins & secretory proteins

25

Golgi apparatus

an organelle in eukaryotic cells consisting of stacks of membranous sacs that modify, store, & ship products of the endoplasmic reticulum

26

lysosome

a digestive organelle in eukaryotic cells

contains hydrolytic enzymes that digest the cell's food & wastes

27

vacuole

a membrane-enclosed sac that's part of the endomembrane system of a eukaryotic cell, having diverse functions

28

central vacuole

a membrane-enclosed sac occupying most of the interior of a mature plant cell, having diverse roles in reproduction, growth, & development

29

peroxisome

an organelle containing enzymes that transfer hydrogen from various substrates to oxygen, producing and then degrading hydrogen peroxide

30

mitochondrion (mitochondria)

an organelle in eukaryotic cells where cellular respiration occurs

enclosed by 2 concentric membranes

where most of the cell's ATP is made