Cells Flashcards
(41 cards)
1
Q
Three original tenets of cell theory
A
- All living things consist of cells
- The cell is the smallest and basic unit of life
- All cells originate from pre-existing cells
2
Q
Tenets of modern Cell Theory
A
- All living things consist of cells
- The cell is the smallest and basic unit of life
- All cells originate from pre-existing cells
Modern additions:
- The activity of an organism depends on the total activity of independent cells.
- Energy flow (metabolism and biochemistry) occurs within cells.
- Cells contain DNA, the hereditary information.
- All cells are basically the same in chemical composition in organisms of similar species.
3
Q
Function of chromatin network
A
- Made of DNA and proteins
- Contains genes (hereditary information)
- Instructs all the activities of the cell
- Packaged as chromosomes for cell division
4
Q
All eukaryotic cells have…
A
- Cell membrane
- Cytoplasm
- Organelles
- Nucleus
5
Q
Only plant cells have…
A
- Cell wall (though fungi also have a cell wall)
- Large central vacuole
- Plastids e.g. chloroplasts
6
Q
Structures making up the cell wall of plants
A
- Primary cellulose wall
- Secondary lignin wall
- Middle pectin lamella
- Pits
- Plasmodesmata
7
Q
Primary cellulose wall function
A
shape
8
Q
Secondary lignin wall function
A
strength
9
Q
Middle pectin lamella function
A
joins cells together
10
Q
Pits in cell wall function
A
ease transport between cells
11
Q
Plasmodesmata function
A
joint cell cytoplasms for communication and transport between plant cells
12
Q
Useful substances made from plant cell walls
A
- Wood
- Paper
- Cork
- Cotton
13
Q
Structures of cell membranes
A
- Phospholipid bi-layer
- Carrier and channel proteins
- Carbohydrates
14
Q
Function of carrier and channel proteins in a cell membrane
A
control movement of larger substances into and out of a cell
15
Q
Function of the carbohydrates on the surface of a cell membrane
A
cell recognition
16
Q
Parts of the phospholipid bi-layer
A
- Hydrophilic head
- Hydrophobic tail
- Hydrophobic tail
- Hydrophilic head
17
Q
Types of movement across a membrane
A
Diffusion
Osmosis
Facilitated transport
Active transport
18
Q
Two types of osmosis
A
Endosmosis (water movement into cell)
Exosmosis (water movement out of cell)
19
Q
Process of diffusion
A
- Passive process (no energy required)
- Non-selective movement along concentration gradient
- From high to low concentrations until equilibrium
- E.g. oxygen
20
Q
Process of osmosis
A
- Selectively permeable membrane
- Passive process (no energy required)
- Movement of water into or out of cell
- Water moves along concentration gradient
- From high water potential to low water potential until equilibrium
21
Q
Process of facilitated transport
A
- Living selectively permeable membrane
- Carrier proteins required
- passive process (no energy required)
- selective movement of substances along concentration gradient using carrier proteins until equilibrium
- e.g. Glucose
22
Q
Process of active transport
A
- living selectively permeable membrane
- carrier proteins required
- active process ATP required
- selective movement of substances
- against a concentration gradient (from low to high)
- e.g. sodium and potassium ions
23
Q
Endocytosis
A
- In animal cells
- Process of taking in food particles and nutrients
- Also called phagocytosis
- structure formed called a food vacuole (membrane bound)
24
Q
Exocytosis
A
- In animal cells
- structure involved called secretory vesicle (membrane bound)
- Process or removing particles and metabolic wastes
- Also called elimination or secretion
25
Other cell membrane structures in animal cells
Microvilli - increase surface area
Pinocytic vesicles - take up liquids
Phagocytic vesicles - take up particles using pseudopodia
26
Structures of the nucleus
Double membrane
Nucleopores
Nucleoplasm
Chromatin network
Nucleolus
27
Two types of endoplasmic reticulum (ER)
Smooth ER - no ribosomes attached
Rough ER - ribosomes attached
28
Function of the endoplasmic reticulum
Connects cell membrane with nucleus
A network of membrane bound tubes
For transporting substances
Rough ER makes and transports proteins
29
Cytoplasm contents
- Water (90%)
- Enzymes
- Protein cytoskeleton
- Organelles
30
Function of ribosomes
Protein synthesis
31
Examples of vacuoles
Contractile vacuole - controls water content of cell
Lysosome - contains peroxidase enzyme
Phagocytic vesicle - contain food particles
Pinocytic vesicle - take up fluids
32
Tonoplast
Membrane that surrounds a vacuole
It can provide turgidity (support) to the cells
33
Structure of a mitochondrion
* Double membrane
* Cristae - internal folds
* Matrix - internal fluid
34
Function of the mitochondrion
* Where cellular respiration takes place
* Production of ATP (energy carrier molecules)
* Provides energy for the cell
35
Golgi body (animal cells) and dictyosomes (plants) structure and function
Stacked flapjack like membrane bound structure
Packaging centre of cell
Sort and store cellular secretions e.g. enzymes
36
Types of plastids (plant cells)
* Leucoplasts - no pigments (storage organelle)
* Chromoplasts - yellow-red pigments
* Chloroplasts - green pigments
37
Structure of a chloroplast
* Double membrane
* Stroma - inner fluid
* Thylakoids - membrane structures with chlorophyl
* Grana - stacked thylakoids
* Inter-granum lamella - membrane bridges between grana
* Occasionally: starch granules
38
Chlorophyll
* Green pigment
* Captures light energy
* Needed for photosynthesis
39
Structure and function of the centrosome
* Made of two centrioles
* act as anchors during cell division
* and form the spindle apparatus
40
Cell differentiation
* A process where cells change size, shape and composition
* to be able to perform specific function
* also called cell specialisation
41
Undifferentiated cells in plants and animals
* Stem cells - animals
* Meristem cells - plants
