Cell Structure and Composition Flashcards Preview

MCD - Introduction to Cells > Cell Structure and Composition > Flashcards

Flashcards in Cell Structure and Composition Deck (31):
1

Definition of a cell

The basic unit from which living organisms are made, consisting of an aqueous solution of organic molecules enclosed by a membrane. All cells arise from existing cells, usually by a process of division.

2

Predominant types of molecules found in cells

Soluble proteins, ions, sugars, nucleotides, amino acids, mRNA, tRNA, lipids, cholesterol, peptides.

3

Size of cells

10-20 micrometres diameter

4

Mass of a cell

1 nanogram

5

Size of a virus

10 nanometres

6

Small protein

40 nanometres

7

Unit of measurement for cell volume

Nanolitres

8

Size of molecules

0.2 nanometres in diameter

9

Function of nucleus

Contain the genetic information for the cell, coordinate the activity of the cell

10

Function of nucleolus

Contains genes for rRNA production

11

Function of nuclear envelope

Contain the nucleus

12

Function of mitochondrion

ATP synthesis

13

Function of rough ER

Synthesis and packaging of proteins

14

Function of smooth ER

Synthesis of lipids

15

Function of ribosomes

Synthesis of protein

16

Function of golgi apparatus

Modification of proteins and packing into vesicles

17

Function of secretory granules

Contain and release contained molecules

18

Function of plasma membrane

Contain and define limits of the cell

19

Function of cytoskeletal components

Provide organisation and control of components of intracellular matrix

20

Essential characteristics of prokaryotic cells

- No membrane bound organelles
- No nucleus
- Some have flagella
- Lesser degree of organisation within cell
- Some have peptidoglycan cell walls
- 70s ribosomes

21

Essential characteristics of eukaryotic cells

- Membrane-bound organelles
- Nucleus
- Some have cilia/microvilli
- Cytoskeleton - high degree of organisation
- No cell wall, only cell membrane
- 80s ribosomes

22

Structural components of phospholipids (in descending order)

Hydrophilic choline head
Phosphate
Glycerol
Two fatty acid tails

23

Explain the formation of phospholipid bilayers in aqueous environments

Hydrophobic tails form hydrophobic core of bilayer, pointing towards the inside of the bilayer. Hydrophilic heads form the two hydrophilic surfaces of the bilayer, facing outwards from the inside of the bilayer. Form a micelle.

24

Permeability properties of phospholipid bilayer membrane

- Selectively permeable
- Impermeable to large molecules and charged molecules
- Permeable to water molecules and small uncharged molecules

25

Functions of membrane proteins

- Increase fluidity of membrane
- Transport of molecules
- Transmission of signals
- Anchors linking intracellular actin filaments to extracellular matrix
- Receptors for hormones
- Cell recognition and adhesion
- Electron carriers
- Enzymes

26

Simple diffusion

Movement of a particle down its concentration gradient

27

Facilitated diffusion

Movement of charged particles through channel proteins down their concentration gradient

28

Active transport

Movement of a particle against its concentration gradient, using ATP in the process.

29

Example of simple diffusion

O2/CO2 molecules through lipid bilayer

30

Example of facilitated diffusion

K+ diffusion through its gated channel protein

31

Example of active transport

Na+/K+ pump, both ions moving against their electrochemical gradients