2.1 structure and function of a cell

Question 1

what features do all eukaryotic cells have in common.

Answer 1

1-the genetic material—DNA
2-A cell membrane comprise of a phospholipid bilayer
3-Filling the cell interior is the jelly-like cytoplasm

Question 2

The Nucleus

Answer 2

contains DNA, which stores and
replicates the genetic information of the cell.

Question 3

Each molecule of DNA in the
nucleus combines with an equal mass of (——) to form a chromosome.

Answer 3

protein

Question 4

nucleolus

Answer 4

a
non-membrane bound structure in the
nucleus, which contains
RNA and proteins/a denser region containing RNA, protein, and chromatin.

Question 5

nuclear envelope

Answer 5

a double membrane consisting of two phospholipid bilayers, which
separates the nucleus from the rest of the cell.

Question 6

nuclear pore complex

Answer 6

a group of proteins
forming openings in
the nuclear envelope

Small particles such as water and ions travel freely through these openings, but the passage of
macromolecules such as RNA is controlled by the nuclear pores

Question 7

ribosome

Answer 7

a structure
composed of
RNA and proteins,
and responsible
for synthesis of
polypeptides in the
cytosol and on the
surface of the rough
endoplasmic reticulum

Question 8

endoplasmic
reticulum (ER)

Answer 8

a complex system
of channels and
sacs composed of
membranes enclosing
a lumen; made up of
two parts, the rough ER
and the smooth ER

Question 9

rough endoplasmic reticulum

Answer 9

ribosome-rich parts
of the ER that look like sandpaper

Question 10

smooth endoplasmic

Answer 10

Regions of the ER that have no bound ribosomes

Question 11

what does the smooth ER do?

Answer 11

MAIN(R synthesizes lipids and lipid-containing molecules such as the
phospholipids that make up membranes.)

Smooth ER performs other functions depending
on the type of cell. For example, in the liver, smooth ER helps detoxify drugs and alcohol. In
the testes and ovaries, smooth ER produces testosterone and estrogen.

Question 12

endomembrane
system

Answer 12

the system
within the cell that
acts to synthesize,
modify, and transport
proteins and other cell
products; includes the
endoplasmic reticulum,
the Golgi apparatus,
vesicles, and the cell
membrane, among
other structures

Question 13

vesicle

Answer 13

a membrane enclosed sac used for
transport and storage

Question 14

Golgi
apparatus

Answer 14

s a
stack of curved
membrane sacs that
packages, processes,
sorts, and distributes
proteins, lipids, and
other substances
within the cell; acts
like a “post office” for
the cell

Question 15

lysosome

Answer 15

a
membrane-bound
vesicle containing
enzymes that catalyze
hydrolysis reactions,
breaking down
macromolecules

catalyze hydrolysis reactions, breaking down macromolecules into smaller molecules that
can be reused by the cell.

Question 16

vacuole

Answer 16

a large,
membrane-bound
sac in plant cells and
some other cells that
stores water, ions,
macromolecules,
sugars, and amino
acids

Question 16

chloroplast

Answer 16

an
organelle in the cells
of photosynthetic
organisms in which
light energy from the
Sun is captured and
stored in the form of
high-energy organic
molecules such as
glucose

Question 17

peroxisome

Answer 17

membrane-bound
sac containing
oxidative enzymes
that break down
excess fatty acids and
hydrogen peroxide,
and participate in the
synthesis of bile acids
and cholesterol

the enzymes in peroxisomes are oxidases
that catalyze redox reactions.

Question 18

mitochondrion

Answer 18

an
organelle in eukaryotic
cells in which high-energy organic
molecules are oxidized
to obtain energy

basically convert
stored energy into usable energy

Question 19

cell wall

Answer 19

a rigid layer
surrounding plant,
algae, fungal, bacterial,
and some archaea cells,
composed of proteins
and/or carbohydrates;
gives the cell its shape

Question 20

cytoskeleton

Answer 20

a network of protein
fibres that extends
throughout the cytosol,
providing structure,
shape, support, and
motility

Question 21

fluid mosaic model

Answer 21

the accepted model
of the cell membrane,
which is a basic
framework of a semifluid phospholipid
bilayer with a mosaic of
proteins; carbohydrates
may be attached to
lipids or proteins

Question 22

what are the main factors that affect fluidity in the fluid mosaic model

Answer 22

Temperature
Presence of double bonds in the fatty acid “tails”
Fatty acid “tail” length

Question 23

The Function of Proteins in a Phospholipid Bilayer

Answer 23

Transport
* Reaction catalysis
Cell recognition
* Signal reception and transduction