Cells Flashcards
1
Q
What does a cell consist of?
A
- each cell contains a living material called protoplasm
- consist of cell surface membrane, nucleus, cytoplasm
2
Q
Cell surface membrane/plasma membrane
A
- surrounds cytoplasm of cell
- made up of lipids and proteins
- partially permeable, control substance entering and leaving cell
3
Q
Cytoplasm
A
- part of protoplasm, between cell surface membrane and nucleus
- where most cell activities occur
- contains organelles which are specialized structures which carry out many functions in cell
4
Q
Nucleus
A
- consists of small round mass of denser protoplasm called nucleoplasm
- surrounded by nuclear envelope (membrane)
- controls cell activities e.g. cell growth, repair worn-out parts
- essential for cell division (rbc cannot divide)
- contain one or more nucleoli and chromatin
5
Q
Cellulose Cell wall
A
- made of cellulose
- protects cell from injury, gives cell fixed shape
- fully permeable
6
Q
Nucleus: Nuclear envelope
A
separates contents of nucleus from rest of cytoplasm
7
Q
Nucleus: Nucleoplasm
A
dense material within nucleus
8
Q
Nucleus: Nucleolus
A
-plays a part in making proteins in cell
9
Q
Nucleus: Chromatin
A
- mass of long thread-like structures found within nucleus
- each chromatin thread made up of proteins and DNA (hereditary info stored in here)
- DNA carries instructions of cell needs for carrying out activities
- during cell division, chromatin threads condense, become highly coiled structures called chromosomes
10
Q
Cytoplasm: Rough endoplasmic reticulum
A
- network of flattened spaces lined with a membrane
- surface appears rough when viewed under electron microscope
- ribosomes attached to its membrane
- outer surface of RER continuous with nuclear envelope
- transports proteins made by ribosomes to Golgi Apparatus for secretion out of cell
11
Q
Cytoplasm: Ribosomes
A
- small round structures
- attached to membrane of ER or lie freely in cytoplasm
- essential in protein synthesis in cell
- those attached to ER usually transported out of cell
- those lying freely in cytoplasm make proteins that are used within cytoplasm in cell
12
Q
Cytoplasm: Smooth Endoplasmic Reticulum
A
- no ribosomes attached to membrane/surface
- more tubular than RER, connected to RER
- synthesis of fats, steroids (sex hormones in mammals)
- detoxification, convert harmful substances to harmless materials
13
Q
Golgi apparatus
A
- disc-like shape
- stack of flattened spaces surrounded by membranes
- vesicles(transport substances within cell) fuse from one side of GA, pinch off from opp side
- GA chemically modifies substances made by ER
- stores and packages these substances in vesicles for secretion out of cell
14
Q
How substances made by organelles in cell are released out of cell
A
- Small vesicles containing substances made by ER, pinched off from ER
- vesicles fuse with GA, release contents in it, substance made by ER may by modified in GA
- Secretory vesicles containing modified substances pinched off from GA, move to cell surface membrane
- Secretory vesicles fuse with cell surface membrane, contents released out of cell
15
Q
Mitochondria
A
- oval/sausage shaped
- aerobic respiration occurs here
- food substances oxidised, release energy
- used fro cell activities e.g. growth, reproduction
