THE CELL Flashcards
1
Q
NUCLEUS
A
- where genetic info stored
- controls cellular structure + activities
- double membrane that forms the nuclear envelope
- holds codes for synthesis of 10,000 different proteins
2
Q
NUCLEOLUS
A
region where rRNA synthesis takes place
3
Q
NUCLEAR ENVELOPE
A
- 2 phospholipid bilayers
- nuclear pores to control passage in + out of nucleus
4
Q
RIBOSOMES
A
- protein synthesis machinery
- links amino acids together under instruction of mRNA
- non-membranous organelles
- found in ALL cell types
- protein synthesis requires all RNA types
- free in cytoplasm or associated with internal membranes
- consists of 2 subunits (small + large) which join together in cytoplasm to form functional unit
5
Q
ENDOPLASMIC RETICULUM
A
- extensive series of membrane bound channels (cisterns)
6
Q
ROUGH ENDOPLASMIC RETICULUM
A
- lies adjacent to nucleus
- attachment of ribosomes
- synthesis of proteins to be secreted, sent to lysosomes or plasma membrane
7
Q
SMOOTH ENDOPLASMIC RETICULUM
A
- extends from the rough ER
- synthesis of fatty acids + steroids
- stores calcium
- detoxification
8
Q
GOLGI APPARATUS
A
- flattened stacks of interconnected membranes
- packaging + distribution of molecules
- vesicles transport molecules to destination
9
Q
VACUOLE
A
- store nutrients for cell energy
- store waste products prior to expulsion
- membrane that surrounds fluid
10
Q
VESICLES
A
- fluid enclosed by lipid bilayer membrane
- can from during exocytosis, phagocytosis + endocytosis
- for transport of materials within cytoplasm
- involved in metabolism, transport + enzyme storage
11
Q
LYSOSOMES
A
- membrane bounded digestive vesicles
- arise from Golgi apparatus
- destroy cells or foreign matter that the cell has engulfed by phagocytosis
- involved in autophagy
12
Q
MITOCHONDRIA
A
- found in ALL types of eukaryotic cells
- cell’s powerhouse
- bounded by membranes (outer, intermembrane space, inner, matrix)
- metabolise sugars to make ATP
- have their own DNA + ribosomes
13
Q
CYTOSKELETON
A
- network of protein fibres found in all eukaryotic cells
- supports shape of cell
- keeps organelles in fixed locations
14
Q
CELL FIBRES
A
- MICROFILAMENTS
- MICROTUBULES (largest)
- INTERMEDIATE FILAMENTS
15
Q
CENTROSOME
A
- region surrounding nucleus in most animal cells
- specialised units are centrioles
- microtubule organising centre
16
Q
CELL MEMBRANE FUNCTIONS
A
- defines cell boundary
- regulates what moves in + out of the cell
- supports cell
- allows cell signalling + cell recognition
17
Q
MEMBRANE STRUCTURE
A
- PHOSPHOLIPIDS
- arranged in bilayer (~50%) - proteins
- inserted in bilayer (~50%) - cholesterol
- makes membrane less permeable to hydrophilic molecules
hydrogen bonding of water holds the 2 layers together, fluid structure
18
Q
DESCRIBE MEMBRANE
A
- not static
- active
- move against each other
- proteins move in + out constantly
- phospholipids mostly move laterally
19
Q
WHAT ALLOWS PHOSPHOLIPIDS TO FORM MEMBRANES?
A
- polar hydrophilic heads
- non-polar hydrophobic tails
the charges allow phospholipids to form membranes
20
Q
MEMBRANE PROTEIN FUNCTIONS
A
- transporters
- enzymes
- cell surface receptors
- cell surface identity markers
- cell-to-cell adhesion proteins
- attachments to cytoskeleton
21
Q
MEMBRANE PORES
A
- extensive non-polar regions within transmembrane protein can create a pore in membrane
- interior is polar to allow water + small polar molecules to pass through
22
Q
3 MAIN PARTS OF A CELL
A
- plasma membrane
- nucleus
- cytoplasm
23
Q
WHY IS NUCLEUS KNOWN AS CONTROL CENTRE?
A
- stores all genetic info needed to control protein synthesis
- proteins essential to structure + function of cells
- controlling their synthesis means nucleus controls cellular operations
24
Q
WHY ARE PROTEINS SYNTHESISED BY RIBOSOMES ATTACHED TO ER DIFFERENT FROM UNATTACHED RIBOSOMES?
A
- attached synthesise proteins for use in specific organelles, plasma membrane or exportation
- unattached/ ‘free’ synthesise proteins for use within cytosol
25
WHERE IS TESTOSTERONE SYNTHESISED?
steroid synthesised in the smooth ENDOPLASMIC reticulum
26
3 DESTINATIONS OF PROTEIN PACKED BY GOLGI APPARATUS
1. insertion into plasma membrane
2. insertion into organelle member
3. removal (by exocytosis) from cell for use elsewhere in body
27
WHAT DOES IT MEAN IF CELL HAS MANY MITOCHONDRIA?
- high energy requirement
- high work load
- e.g. skeletal muscles or light receptor cells
28
WHY IS IT ESSENTIAL FOR LYSOSOMES TO HAVE MEMBRANES?
so powerful they could destroy the cell
29
SECRETORY VESICLES
transports protein out of cell via exocytosis
30
MEMBRANE VESICLES
carries new molecules to the plasma membrane
31
TRANSPORT VESICLE
carries molecules to other intercellular destinations e.g. lysosomes
32
MAIN COMPONENTS OF PLASMA MEMBRANE
- phospholipid
- cholesterol
- glycolipid
- protein
