Structure And Function of Cellular Organelles Flashcards
Who coined the term ‘cell’?
Robert Hooke, after observing a sliver of cork under a microscope
State the cell theory
- All living things are made of cells - Theodore Schwann and Matthias Schleiden (1839)
- The cell is the smallest living units with the structure and function of all organisms
- All cells arise from pre-existing cells (Rudolf Virgo’s 1889)
What are the characteristics of a cell?
- Surrounding membrane
- Protoplasm
- Organelles
- Nucleus
What are the types of organelles?
Membrane bound
Bacteria-like
What is peculiar to prokaryotic cells?
No membrane-bound nucleus or organelles
What is the Endosymbiotic Theory?
It explains the evolution of modern cells from cells and symbiotic bacteria.
Describe the plasma membrane briefly
It contains the cell contents. It is made up of a double layer of phospholipids, embedded with proteins which can also be found in the bilayer.
What are the functions of the plasma membrane?
- Defines boundary
- Regulates movement of molecules
- Shape and rigidity
- Separates cells
What are the types of membrane proteins?
Peripheral membrane proteins
Integral membrane proteins
Examples of peripheral membrane proteins
Phospholipase
Cholesterol
Oxidase
Examples of integral membrane proteins
Glycophorin, Gap junctions
What are the kinds of membrane proteins based on function?
Channels/Transporters
Receptors
Glycoproteins
Enzymes
Which membrane proteins identify cell types?
Glycoproteins
Which membrane proteins recognize certain chemicals?
Receptors
What is the cytoplasm and its components?
It is a viscous fluid in the cell in which organelles are suspended.
Components of cytoplasm: –Interconnected filaments & fibers –Fluid = cytosol –Organelles (not nucleus) –Storage substances like glycogen, oxalates and starch
What is the lysosome and its functions?
A membrane-bound vesicle at the site of hydrolysis that Contains hydrolytic digestive enzymes.
Functions
–AIDS in cell renewal
–Break down old cell parts
–Digests invaders
What are examples of hydrolytic digestive enzymes?
Lysozyme, Phosphodiesterase, Hyaluronidase, Acid Phosphatase, Estersse, Nuclease, Protease
What are peroxisomes?
They are oxidative membrane-bound organelles in eukaryotes
Where are glycoproteins found?
In the non-cytoplasmic part of the membrane.
What constitutes the cytoskeleton?
Filaments and fibers
What are the types of fibres present in cytoskeleton?
Microfilaments
Microtubules
Intermediate filaments
What are the functions of cytoskeleton?
Mechanical support
Anchorage of organelles
Movement of substances
What are the membrane-bound organelles?
Nucleus Endoplasmic recticulum Golgi apparatus Lysosomes Vacuoles
What is the function of the nucleoli?
Directs synthesis of RNA
Forms ribosomes
What is the primary function of the ER?
Transport of substances within cells
What is the function of Rough ER?
Manufacture proteins
May modify proteins from ribosomes
What is the function of smooth ER?
It has enzymes that help build molecules
–Carbohydrates
–Lipids
What is the function of Golgi Apparatus?
- Involved in synthesis of plant cell wall
- Packaging & shipping station of cell
Vacuoles are more common in plants than in animals.
True or False?
True
What are the contents of vacuoles?
Water.
Food
Waste
What are the bacteria-like organelles?
Mitochondrion
Chloroplasts
State one peculiar property of bacteria-like organelles.
They store and release energy.
What is the primary function of mitochondria?
They break down fuel molecules via cellular respiration to release energy as ATP.
Give examples of fuel molecules utilized by the mitochondrion
Glucose
Fatty acids
Give an enzyme contained in the mitochondria
They contain TCA cycle enzymes like alpha-ketoglutarate dehydrogenase
Mention two ways through which ATP is formed.
Oxidative phosphorylation
Substrate-level phosphorylation
What is the site for oxidative phosphorylation?
In the mitochondrion
What is the site for substrate level phosphorylation?
The matrix of the mitochondrion
What are plastids?
Found in plant cells, they are the site for the manufacture and storage of important chemical compounds.
What are the types of plastids?
Proplastids Chloroplasts Chromoplasts Leucoplasts Proteinoplasts Aminoplasts
Where are proplastids found?
The meristematic cells of roots and shoots
What are proplastids?
Small, colorless or pale green undifferentiated plastids that develop into other plastids
Chloroplasts are derived from…
…photosynthetic bacteria
Functions of chromoplasts
No chlorophyll
Synthesis and retaining of carotenoid pigments
What are leucoplasts?
Unpigmented plastids that may synthesize starch
What are the types of cells
Prokaryotic
Eukaryotic
How does movement across the plasma membrane happen
Free movement
Use of carrier proteins
Components of cytoplasm
- Interconnected filaments and fibres
- Fluid (cytosol)
- Organelles
- Storage substances
Glycoproteins can be used to identify cell types
True
