Wow slide 6

Question 1

1 micrometer (micron)

Answer 1

1/1000 of a mm

Question 2

1 nanometer

Answer 2

1/1000 of a micron

Question 3

Light microscopes

Answer 3

can magnify effectively to

about 1,000 times the size of the actual specimen

Question 4

Most subcellular structures are too small to be

resolved by a light microscope.

Answer 4

Various techniques in light microscopy can

increase visibility of structures

Question 5

Scanning electron microscopes (SEMs)

Answer 5

focus a beam
of electrons onto the surface of a specimen and collect
emitted electrons to provide images that look 3-D

Question 6

Transmission electron microscopes (TEMs)

Answer 6

focus a
beam of electrons on a specimen and collect electrons
that pass through the specimen.

Question 7

TEMs are used mainly to study

Answer 7

the internal structure of
cells and can magnify up to 1 million times the size of the
actual specimen.

Question 8

Cell Theory

Answer 8

All living things are composed of cells.

Question 9

Basic features of all cells*

Answer 9

– Semiautonomous, reproduce
– Carry a genetic program in the form of DNA
– Enclosed by a plasma membrane
– Semifluid internal substance called cytoplasm
– Contain ribosomes (make proteins)

Question 10

Prokaryotic Cells

Answer 10

Simple, prokaryotic bacteria
cells have existed for at
least 3.5 billion years.

Question 11

Cellular processes occur
diffusely within the
prokaryotic cell.

Answer 11

Genetic material is in the
form of a single large,
naked DNA molecule.

Question 12

Eukaryotic cells appear

Answer 12

in the fossil record 1.5 billion years
after the first bacteria and are the cells that comprise all
living organisms besides bacteria.

Question 13

Eukaryotic cells have a distinct, membrane bound nucleus

Answer 13

containing the cell’s genetic material.

Question 14

Eukaryotic cells have separate organelles

Answer 14

specialized

structures that perform specific functions.

Question 15

Robert Hooke (1653 - 1703) was the first to
observe and describe cells in
plant tissues

Answer 15

He published the bestseller
“Micrographia” of images he
observed with his microscope

Question 16

A high surface-to-volume ratio
facilitates exchange of materials with
the surrounding environment.

Answer 16

Dividing a volume into smaller cells

increases the total surface area

Question 17

The plasma membrane is

Answer 17

a selective barrier comprised primarily of a

phospholipid bilayer that encloses the interior of the cell, the cytoplasm

Question 18

plasma membrane

Answer 18

It maintains the differences between internal and external environments

Question 19

Plant and bacteria
cells also have a
cell wall

Answer 19

in
addition to their
cell membrane
that protects and
supports the cell

Question 20

The nucleus of a cell

Answer 20

contains the cell’s genetic
material. Every cell has a
copy of the organism’s
“blueprint”

Question 21

Pores in the membrane of the

nucleus

Answer 21

allow molecules to
move between the nucleus
and the cytoplasm

Question 22

Within the nucleus the
nucleolus is the site where
ribosomal RNA (rRNA) is
synthesized.

Answer 22

The rRNA exits the nucleus
and assembles into
ribosomes in cytoplasm

Question 23

The endoplasmic reticulum (ER)

Answer 23

is an extensive folded surface
continuous with the plasma
membrane within which proteins,
lipids (fats, steroids), and
phospholipids are produced

Question 24

Ribosomes

Answer 24

are the
structures that read the
instructions in the genetic
“blueprint” and assemble
proteins.

Question 25

Ribosomes can occur

Answer 25

freely within the cytoplasm or attached to the endoplasmic reticulum

Question 26

The Golgi apparatus is a

Answer 26

``` complex of membrane vesicles that function in storage, processing, and packaging of proteins produced by the rough endoplasmic reticulum ```

Question 27

Lysosomes

Answer 27

are vesicles that contain hydrolytic enzymes used to break down various macromolecules in the cell

Question 28

The endomembrane | system*

Answer 28

``` is comprised of the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, vesicles and the plasma membrane. ```

Question 29

Phagocytosis

Answer 29

is the formation of a food vacuole | which is merged with a lysosome for digestion.

Question 30

Autophagy

Answer 30

is the destruction of cellular components by | collecting them in a vacuole that merges with a lysosome.

Question 31

Chloroplasts

Answer 31

Possess a membrane system dividing the chloroplast into three compartments (intermembrane space, stroma, thylakoid) Contain the green pigment chlorophyll that absorbs solar energy for use in synthesizing sugars Are self-replicating and contain their own genetic material independent of the cell as a whole

Question 32

Mitochondria

Answer 32

are the “powerhouses” of the cell. Chemical reactions occurring on the surface of an inner membrane produce energy carrying molecules (ATP).

Question 33

Mitochondria are self-replicating

Answer 33

and have their own | genetic material independent of that of the cell as a whole

Question 34

Endosymbiosis

Answer 34

is one organism living inside another.

Question 35

The endosymbiotic theory

Answer 35

of the origin of eukaryotes states that some organelles such as mitochondria are derived from once free-living bacteria that colonized the cytoplasm of other single-celled organisms either through ingestion or parasitism

Question 36

Mitochondria (and chloroplasts in plant cells) have their | own

Answer 36

genomes with DNA sequences closer to those of bacteria than to those in the nuclear DNA of the cells in which they occur

Question 37

Mitochondria (and chloroplasts in plant cells) have their | own

Answer 37

genomes with DNA sequences closer to those of bacteria than to those in the nuclear DNA of the cells in which they occur

Question 38

cytosol

Answer 38

The jellylike substance in which the organelles of the | cytoplasm are suspended is called

Question 39

A fibrous network called the cytoskeleton

Answer 39

spans the cytosol | to support the membranes and organelles of the cell.

Question 40

Cytoskeleton includes

Answer 40

actin, intermediate filaments, and | microtubules.

Question 41

Actin

Answer 41

is arranged to bear pulling forces (tension). In muscle cells, actin is pulled upon by filaments comprised of the motor protein myosin

Question 42

Amoeboid movement

Answer 42

of the cell is achieved by the action of actin microfilaments that extend a pseudopodium outward from the surface of the cell.

Question 43

Cytoplasmic streaming

Answer 43

moves the mass of the cell | in the direction of the pseudopodium.

Question 44

The motor protein dynein

Answer 44

moves organelles and other materials within the cell by “walking” along microtubules.

Question 45

Arrangements of microtubules are responsible

Answer 45

``` for the beating of flagella and cilia, external appendages used for locomotion ```

Question 46

Flagella and cilia

Answer 46

contain dynein that acts against the | microtubule structure to produce movement.

Question 47

Microvilli

Answer 47

are fingerlike projections of the plasma membrane supported by bundles of actin.

Question 48

Microvilli increase

Answer 48

the area of absorptive and digestive surfaces.

Question 49

Tight junctions

Answer 49

``` proteins across membranes bind cells closely together preventing molecules from passing between (e.g. intestinal cells) ```

Question 50

Desmosomes

Answer 50

``` “spot welds” between cells formed from proteins and bundles of intermediate filaments that increase the strength of tissues (e.g. skin cells) ```

Question 51

Gap junctions

Answer 51

``` – tiny canals between cells through which cytoplasm and small molecules can pass (e.g. in nerve and muscle cells) ```

Question 52

cell junctions

Answer 52

tight junctions, desmosomes, gap junctions

Question 53

Animal cells are surrounded by a complex extracellular matrix

Answer 53

comprised of glycoproteins (proteins bonded to carbohydrates) including collagen.

Question 54

Functions in:

Answer 54

* Support * Adhesion * Movement * Regulation

Question 55

The cell wall of plants

Answer 55

``` is an extracellular structure that protects and supports the cell and helps maintain water balance. ```

Question 56

plasmodesmata

Answer 56

The nonliving cell walls of plants are perforated with channels called plasmodesmata that connect the cytoplasm of cells