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Flashcards in Cell Structure Deck (33)
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1

Cell membrane

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.

2

Plant cell wall

Made of cellulose (a polysaccaride).

3

Bacteria cell wall

Made of peptidoglycan (protein and sugar).

4

Fungi cell wall

Made of chitin (polysaccaride similar to cellulose.

5

Simple Diffusion

1. Allows gas or dissolved substances to cross the membrane.
2. A substance moves from high concentration to low concentration until equilibrium is reached.

6

Facilitated Diffusion

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.

7

Active Transport

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

8

Bulk Transport

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.

9

Hypertonic solution

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.

10

Hypotonic solution

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

11

Isotonic

1. Exactly the same concentration as the cell
2. In human cells, it's at .9% NaCl solution

12

Osmosis

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.

13

Organelles

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.

14

Prokaryotic

No organelles

15

Vacuole

Stores waste and other material

16

Ribosomes

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

17

Smooth endoplasmic reticulum

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

18

Rough endoplasmic reticulum

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

19

Golgi apparatus

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

20

Mitochondria

1. Functions in respiration
2. Produces ATP

21

Lysosomes

Digest foreign substances and worn out organelles

22

Centrioles

Help to form the spindle during mitosis

23

Nucleus

Control center of cells, contains DNA

24

Nucleolus

1. Located in nucleus
2. Controls ribosome synthesis (rRNA)

25

Enzymes

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.

26

Active site

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

27

What happens to an enzyme after a reaction?

It is still reusable

28

Substrate

Reactants in an enzyme catalyzed reaction

29

Denatured

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.

30

Coenzymes

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