Module 1.3: The Cell

Question 1

The cell

Answer 1

1) basic & smallest unit of life
2) can carry out all activities associated with life

Question 2

Metabolism

Answer 2

The chemical reactions that take place inside of the cell

Question 3

What is cell theory?

Answer 3

(1) cells are the basic living units of organization in all organisms

(2) all cells come from other cells

Question 4

Organelles are

Answer 4

• small specialized structures within the cell

-cell as factory (organelles would be each individual department contributing to the cells life functions)

Question 5

Prokaryotic cells

Answer 5

-(also called prokaryotes)

-considered simple cells

-have three defining characteristics: (1) size, (2) non-enclosed genetic material and (3) lack of organelles and other internal membrane bound structures.

Question 6

Prokaryotic cells are typically smaller than eukaryotic cells

Answer 6

• Most are between 1-10 (micrometers)
• 1/30,000 of an inch

-cannot be seen with the naked eye.

Question 7

The DNA of a prokaryotic cell is not

Answer 7

enclosed within a nuclear membrane (prokaryotic means “before the nucleus”).

genomic material remains unbound within the cytoplasm

The area where this genetic material is located is referred to as the** nucleoid**

Question 8

cytoplasm

Answer 8

(interior) of the cell

Question 9

Ribosomes are responsible for

Answer 9

linking together amino acids, as specified by RNA, in order to generate proteins

Question 10

Prokaryotic cells do not contain

Answer 10

organelles

Question 11

Beyond the plasma membrane, the cell wall

Answer 11

is rigid in varying degree depending on the species.

Question 12

Fimbriae

Answer 12

are protein structures located on the outside of the cell that are used for attachment to other cells.

Question 13

Flagella

Answer 13

are whip like structures found on some prokaryotes and serve as a mechanism of movement.

Question 14

Glycocalyx

Answer 14

is a glycoprotein or glycolipid outer coating that allows for protection.

The “coat” that protects the cell

Question 15

Eukaryotic cells are more

Answer 15

complex than prokaryotic cells

Question 16

The Nucleus

Answer 16

surrounded by a porous, double membrane (envelope) (two layers of walls)

is the most prominent organelle in the cell

Enclosed in the nucleoplasm

Question 17

Ribosomes are complexes

Answer 17

of tiny manufacturing plants that assemble proteins.

Question 18

Genes

Answer 18

The information necessary to determine which proteins a cell manufactures

found in specific sequences of nucleotides called “genes”

Question 19

Endoplasmic reticulum (ER)

Answer 19

extension of the outer membrane of the nucleus

Question 20

Rough endoplasmic reticulum (RER)

Answer 20

Part of ER that has ribosomes attached. Ribosomes appear bumpy

Question 21

Smooth endoplasmic reticulum (SER)

Answer 21

Part of the ER which is responsible for the synthesis of lipids, steroids, and phospholipids

Question 22

What do transport vesicles do?

Answer 22

Carry protein & lipids from the ER to Golgi apparatus

Question 23

Lysosomes (“lysis” means to disintegrate)

Answer 23

are membrane-enclosed organelles that contain hydrolytic enzymes capable of degrading unwanted cellular debris such as proteins, lipids, nucleic acids and carbohydrates.

Question 24

autophagy

Answer 24

Once cellular organic matter is broken into their building block monomers, these molecules can later be recycled into new biomacromolecules in a process called

Question 25

Mitochondria

Answer 25

are double membrane-enclosed (phospholipid bilayer) organelles that are the site of cellular respiration.

Question 26

Cellular respiration is

Answer 26

the process of using oxygen to generate ATP. Thus, the mitochondria can be considered the ‘power house’ of the cell.

Question 27

Peroxisomes

Answer 27

small, membrane bound sacs that contain enzymes specific for dissolving fats, amino acids, and hydrogen peroxide

Question 28

Cytoskeleton

Answer 28

Proteins that give cells structural support, anchor organelles & facilitate changes in cellular shape

Question 29

Microtubules are

Answer 29

Thickest of 3 protein fibers, cylindrical tubes

Question 30

9 + 2 arrangement

Answer 30

is nine pairs of microtubules that are arranged in a circle with two additional microtubules in the center of the circle.

Question 31

Microfilaments are

Answer 31

thinner and made of two intertwined protein polymers of actin.

Question 32

Intermediate filaments consist

Answer 32

of a variety of fibrous protein subunits, coiled into cables.

Question 33

Extracellular matrix (ECM)

Answer 33

is the environment surrounding cells.

Question 34

Fibronectin connects to

Answer 34

cell surface receptors, called *integrins*, that extend through the plasma membrane and into the cytosol.

Question 35

Cell junctions are

Answer 35

small channels, spaces, or pores so adjacent cells can communicate with one another. ## Footnote Three main types of junctions are tight junctions, desmosomes, and gap junctions.

Question 36

Tight junctions can be thought of as a belt;

Answer 36

they are mechanical structures that wrap around the cell to prevent extracellular fluid (ECF) from leaking.

Question 37

Desmosomes are

Answer 37

also mechanical, and act as snaps, or fasteners, that lock together along the longitudinal edge of the cell.

Question 38

Gap junctions

Answer 38

are tiny pores or channels that allow for the passage of sugars, ions, and amino acids to flow from cell to cell.

Question 39

The cell membrane (plasma membrane)

Answer 39

is the outermost constituent of the cell.

Question 40

In 1972, the fluid-mosaic model of membrane structure was introduced, which proposes

Answer 40

that the membrane is a phospholipid double (bi-layer) in which proteins are either partially or entirely embedded, like tiles in a mosaic picture.

Question 41

Most of the lipids in the membrane are amphipathic phospholipids which

Answer 41

which self-assemble into a bi-layer with their polar (hydrophilic) heads comprising the inner and outer faces of the membrane and their non-polar (hydrophobic) tails facing each other to form the core of the membrane.

Question 42

Cholesterol may be present in some membranes,

Answer 42

giving extra strength and flexibility to the membrane.

Question 43

Proteins are the other major

Answer 43

constituent of membranes and can be present in a variety of ways.

Question 44

Integral proteins

Answer 44

usually function as membrane channels, signaling receptors, or adhesion points; they span across the lipid bilayer as they simultaneously embed themselves in both the inner and outer membrane of the cell.

Question 45

Peripheral proteins

Answer 45

can be found embedded in either the inner or outer surfaces of the membrane

Question 46

Glycoproteins are a group of

Answer 46

proteins that have carbohydrate (sugar) chains attached, most often occurring on protein associated with the cell membrane.

Question 47

What is the purpose of the nucleoplasm?

Answer 47

Provides a safe place where dna replication and transcription can occur within the nucleus