Cell Structure

Question 1

Cell membrane

Answer 1

1. Forms the outer layer, made of lipids and protein.
2. The nucleus is bounded by a membrane, which has pores to allow substances to enter or exit.
3. Is selectively permeable, only allowing some substances through.
4. Is hydrophobic, so it’s difficult for hydrophilic substances to cross.

Question 2

Plant cell wall

Answer 2

Made of cellulose (a polysaccaride).

Question 3

Bacteria cell wall

Answer 3

Made of peptidoglycan (protein and sugar).

Question 4

Fungi cell wall

Answer 4

Made of chitin (polysaccaride similar to cellulose.

Question 5

Simple Diffusion

Answer 5

1. Allows gas or dissolved substances to cross the membrane.

2. A substance moves from high concentration to low concentration until equilibrium is reached.

Question 6

Facilitated Diffusion

Answer 6

1. Includes polar molecules, or molecules that are too big to cross on their own
2. A substance moves from high concentration to low concentration until equilibrium is reached.
3. Proteins form specialized channels (pores) across membrane that are specific for particular substances, or could act as carrier molecules to pull the substance through
4. Often used to transport ions and glucose.

Question 7

Active Transport

Answer 7

1. Moves a substance from low concentration to high concentration, or against concentration gradient
2. Uses ATP
3. Also relies on membrane proteins, doesn’t matter if substance is hydrophobic or hydrophilic

Question 8

Bulk Transport

Answer 8

1. Movement of large items across cell membrane
2. During endocytosis, the cell takes in a particle by engulfing it in a vesicle.
3. During exocytosis, particle in a vesicle is released to the outside by fusing the vesicle with the membrane.

Question 9

Hypertonic solution

Answer 9

A solution that is more concentrated than a cell’s cytoplasm. The larger amount of water inside the cell will leave, and it will shrivel up.

Question 10

Hypotonic solution

Answer 10

Solution is more dilute than cytoplasm, cell could swell up.

Question 11

Isotonic

Answer 11

1. Exactly the same concentration as the cell

2. In human cells, it’s at .9% NaCl solution

Question 12

Osmosis

Answer 12

1. Movement of water across the cell membrane, down its concentration gradient.
2. Water is hydrophilic and must cross by facilitated diffusion. Cells have many water channels.

Question 13

Organelles

Answer 13

1. Perform specific functions for the cell
2. Contained in the cytoplasm
3. All organelles except for the ribosomes are bound by a membrane, and the nucleus and mitochondria are bound by 2.

Question 14

Prokaryotic

Answer 14

No organelles

Question 15

Vacuole

Answer 15

Stores waste and other material

Question 16

Ribosomes

Answer 16

1. Sites of protein synthesis
2. Those that are free in the cytoplasm make proteins for the cell
3. Those that are bound make proteins for membranes or for outside the cell

Question 17

Smooth endoplasmic reticulum

Answer 17

System that transports substances (like lipids) around the cell using lumen.

Question 18

Rough endoplasmic reticulum

Answer 18

1. Ribosomes are bound to it
2. Specifically synthesize membrane proteins (like channels) or secreted proteins
3. Assists with transport
4. Provides support for cell structure

Question 19

Golgi apparatus

Answer 19

Sorts and packages proteins made on rough ER, can transport outside the cell.

Question 20

Mitochondria

Answer 20

1. Functions in respiration

2. Produces ATP

Question 21

Lysosomes

Answer 21

Digest foreign substances and worn out organelles

Question 22

Centrioles

Answer 22

Help to form the spindle during mitosis

Question 23

Nucleus

Answer 23

Control center of cells, contains DNA

Question 24

Nucleolus

Answer 24

1. Located in nucleus

2. Controls ribosome synthesis (rRNA)

Question 25

Enzymes

Answer 25

1. Biological catalysts that act to facilitate a reaction between 2 molecules to form a product molecule.
2. Specific to certain substrates and specific reactions
3. Determine which chemicals will react to carry out reactions in a cell.

Question 26

Active site

Answer 26

Place where reactants combine to form a substrate on an enzyme.

Question 27

What happens to an enzyme after a reaction?

Answer 27

It is still reusable

Question 28

Substrate

Answer 28

Reactants in an enzyme catalyzed reaction

Question 29

Denatured

Answer 29

1. Loss of shape in an enzyme
2. If an enzyme is denatured, it can’t run reactions
3. Can be caused by established standards for temperature or pH going out of range.

Question 30

Coenzymes

Answer 30

1. Molecules that help enzymes to work faster or to carry out reactions.
2. Vitamins act as coenzymes.
3. Are typically organic molecules

Question 31

Cofactors

Answer 31

1. Help with binding to active site

2. Are typically metal ions (irons)

Question 32

Pinocytosis

Answer 32

Ingestion of liquid into a cell by the budding of small vesicles from the cell membrane.

Question 33

-ase

Answer 33

Typical suffix denoting an enzyme.