Ch 04: Cell Structure

Question 1

cell wall

Answer 1

rigid cell covering comprised of various molecules that protects the cell, provides structural support, and gives shape to the cell

Question 2

central vacuole

Answer 2

large plant cell organelle that regulates the cell’s storage compartment, holds water, and plays a significant role in cell growth as the site of macromolecule degradation

Question 3

centrosome

Answer 3

region in animal cells made of two centrioles that serves as an organizing center for microtubules

Question 4

chlorophyll

Answer 4

green pigment that captures the light energy that drives the light reactions of photosynthesis

Question 5

chloroplast

Answer 5

plant cell organelle that carries out photosynthesis

Question 6

chromatin

Answer 6

protein-DNA complex that serves as the chromosomes’ building material

Question 7

chromosome

Answer 7

structure within the nucleus that comprises chromatin that contains DNA, the hereditary material

Question 8

cilium
(plural = cilia)

Answer 8

short, hair-like structure that extends from the plasma membrane in large numbers and functions to move an entire cell or move substances along the cell’s outer surface

Question 9

cytoplasm

Answer 9

entire region between the plasma membrane and the nuclear envelope, consisting of organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals

Question 10

cytoskeleton

Answer 10

protein fiber network that collectively maintains the cell’s shape, secures some organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently

Question 11

cytosol

Answer 11

the cytoplasm’s gel-like material in which cell structures are suspended

Question 12

desmosome

Answer 12

linkages between adjacent epithelial cells that form when cadherins in the plasma membrane attach to intermediate filaments

Question 13

electron microscope

Answer 13

an instrument that magnifies an object using an electron beam that passes and bends through a lens system to visualize a specimen

Question 14

endomembrane system

Answer 14

group of organelles and membranes in eukaryotic cells that work together modifying, packaging, and transporting lipids and proteins

Question 15

endoplasmic reticulum (ER)

Answer 15

series of interconnected membranous structures within eukaryotic cells that collectively modify proteins and synthesize lipids

Question 16

eukaryotic cell

Answer 16

cell that has a membrane-bound nucleus and several other membrane-bound compartments or sacs

Question 17

extracellular matrix

Answer 17

material secreted from animal or fungal cells that provides mechanical protection and anchoring for the cells in the tissue

Question 18

flagellum

Answer 18

(plural = flagella) long, hair-like structure that extends from the plasma membrane and moves the cell

Question 19

gap junction

Answer 19

channel between two adjacent animal cells that allows ions, nutrients, and low molecular weight substances to pass between cells, enabling the cells to communicate

Question 20

Golgi apparatus

Answer 20

eukaryotic organelle comprised of a series of stacked membranes that sorts, tags, and packages lipids and proteins for distribution

Question 21

intermediate filament

Answer 21

cytoskeletal component, comprised of several fibrous protein intertwined strands, that
-bears tension,
-supports cell-cell junctions, and
-anchors cells to extracellular structures

Question 22

light microscope

Answer 22

an instrument that magnifies an object using a beam of visible light that passes and bends through a lens system to visualize a specimen

Question 23

lysosome

Answer 23

organelle in an animal cell that functions as the cell’s digestive component; it breaks down proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles

Question 24

microfilament

Answer 24

the cytoskeleton system’s narrowest element; it provides rigidity and shape to the cell and enables cellular movements

Question 25

microscope

Answer 25

an instrument that magnifies an object

Question 26

microtubule

Answer 26

the cytoskeleton system’s widest element; it helps the cell:
-resist compression,
-provides a track along which vesicles move through the cell,
-pulls replicated chromosomes to opposite ends of a dividing cell, and
-is the structural element of centrioles, flagella, and cilia

Question 27

mitochondria

Answer 27

(singular = mitochondrion) cellular organelles responsible for carrying out cellular respiration, resulting in producing ATP, the cell’s main energy-carrying molecule

Question 28

nuclear envelope

Answer 28

double-membrane structure that constitutes the nucleus’ outermost portion

Question 29

nucleoid

Answer 29

central part of a prokaryotic cell’s central part where the chromosome is located

Question 30

nucleolus

Answer 30

darkly staining body within the nucleus that is responsible for assembling ribosome subunits

Question 31

nucleoplasm

Answer 31

semi-solid fluid inside the nucleus that contains the chromatin and nucleolus

Question 32

nucleus

Answer 32

cell organelle that houses the cell’s DNA and directs ribosome and protein synthesis

Question 33

organelle

Answer 33

compartment or sac within a cell

Question 34

peroxisome

Answer 34

small, round organelle that:
-contains hydrogen peroxide,
-oxidizes fatty acids and amino acids, and
-detoxifies many poisons

Question 35

plasma membrane

Answer 35

phospholipid bilayer with embedded (integral) or attached (peripheral) proteins, and separates the cell’s internal content from its surrounding environment

Question 36

plasmodesma

Answer 36

(plural = plasmodesmata) channel that passes between adjacent plant cells’ cell walls, connects their cytoplasm, and allows transporting of materials from cell to cell

Question 37

prokaryote

Answer 37

unicellular organism that lacks a nucleus or any other membrane-bound organelle

Question 38

ribosome

Answer 38

cellular structure that carries out protein synthesis

Question 39

rough endoplasmic reticulum (RER)

Answer 39

region of the endoplasmic reticulum that is studded with ribosomes and engages in protein modification and phospholipid synthesis

Question 40

smooth endoplasmic reticulum (SER)

Answer 40

region of the endoplasmic reticulum that has few or no ribosomes on its cytoplasmic surface and
-synthesizes carbohydrates, lipids, and steroid hormones;
-detoxifies certain chemicals (like pesticides, preservatives, medications, and environmental pollutants), and
-stores calcium ions

Question 41

tight junction

Answer 41

protein adherence that creates a firm seal between two adjacent animal cells

Question 42

unified cell theory

Answer 42

a biological concept that states that one or more cells comprise all organisms; the cell is the basic unit of life; and new cells arise from existing cells

Question 43

vacuole

Answer 43

membrane-bound sac, somewhat larger than a vesicle, which functions in cellular storage and transport

Question 44

vesicle

Answer 44

small, membrane-bound sac that functions in cellular storage and transport; its membrane is capable of fusing with the plasma membrane and the membranes of the endoplasmic reticulum and Golgi apparatus