Organelles and functions Flashcards
1
Q
Nucleus
A
- Organelle containing DNA + RNA + protein, surrounded by nuclear envelope with pores
- usually largest organelle of cell (5 to 20 μm)
- contain at least 1 nucleolus
2
Q
Mitochondria
A
- rod like structures with inner + outer structures that are the site of aerobic respiration
- cristae (infolding of inner membrane) and matrix (inner space surrounded by cristae)
- can contain its own DNA and a large variety of enzymes
- ‘powerhouse of cell’ : any cell with energy demanding function will contain large amounts of mitochondria
- around 0.5–1 μm
- Endosymbiotic theory: mitochondria and chloroplasts were thought to originate as symbiotic bacteria
3
Q
Cytoplasm
A
- jelly- like liquid that makes up bulk of cell (contains organelles)
- contains most of what is needed to carry out day-to-day tasks of living
- holds component of cell and prevents them from taking damage
- protoplasm: cytoplasm + nucleus
4
Q
Centriole
A
- bundles of tubules found near nucleus & involve in cell division by production of spindle of microtbules that move microsomes
- each one is made up of bundle of 9 tubules (0.5μm x 0.2 μm)
- involved in cell division: they pull apart to produce spindle of microtubules that are involved in movement of chromosomes
5
Q
Nucleolus
A
- extra dense area of almost pure DNA bonded to protein found in nucleus when cell is not actively dividing
- around 0.5 to 5 µm
6
Q
Cell surface Membrane
A
- important as both an outer boundary to cell in in multitude of internal membranes
- controls movement of substances
- localises enzymes in reaction pathways (e.g. respiration, photosynthesis)
- made up of phospholipid bilayer: hydrophillic tails hide inside layer, vice versa
7
Q
Ribosome
A
- used to make proteins (protein synthesis)
- recieves genetic information from
8
Q
Lysosome
A
- small, round membranous vesicles formed by Golgi bodies which contain group of digestive enzymes
- gets rid of worn and senile cells & organelles which no longer have benefits
- digests large molecules of nutrients engulfed by cell and change them into structurally simpler substances
- 0.1 μm to 1.2 μm
9
Q
Cytoskeleton
A
- dynamic 3D web-like structure made up of microfilaments and microtubules that fills cytoplasm and gives structure, keeping organelles in place and enabling movements and transport within cell
- a feature in all eukaryotic cells
10
Q
Rough Endoplasmic Reticulum (RER)
A
- membrane bound organelle located near the nucleus made up of thin, fluid filled membranes that are stacked together
- folds and packages proteins and sends them to the Golgi Apparatus
- individual cisternae are usually around 0.5 µm in diameter
11
Q
Smooth Endoplasmic Reticulum (SER)
A
- similar to RER, but less bumpy (without ribosomes on surface)
- synthesises lipids e.g. such as cholesterol, and other molecules such as steroids and hormones for use inside the cell and for export outside of the cell
- when exporting these molecules the SER packages them and sends them to the Golgi Apparatus
- also involved in detoxification
- can range from 0.05 to 0.1 µm
12
Q
Golgi Apparatus
A
- package proteins and lipids that are destined for export outside of the cell or to the cell surface membrane
- 0.5 to 2.0 μm
13
Q
Vacuole
A
- fluid filled cavity with cytoplasm of cell surrounded by membrane (not permanent feature in animal cell)
- white blood cells in higher animals form similar vacuoles around engulfed pathogens
- contractile vacuoles allow water content of cytoplasm to be controlled
14
Q
Chloroplast
A
- synthesise food by process of photosynthesis
- contains chlorophyll (used in photosynthesis), its own circular DNA, stroma (fluid-filled space surrounding the grana that contains DNA)
- has a double membrane
- 4-10 µm in diameter
15
Q
Plasmid
A
- small, circular DNA molecules that carry extra genetic information often including genes for antibiotic resistance
- independent of chromosomal DNA, can replicate on their own
- can be transferred from 1 bacterium to another in form of sexual reproduction using pili
15
Q
A
