Anatomy of the Cell Flashcards
What is the cell membrane? (Plasmalemma)
A biomolecular layer of Amphipathic phospholipids
What are the functions of the cell membrane?
Selectively permeable, Allows substances such as water and small hydrophobic molecules to enter the cell while preventing Charged ions.
What can be found within the Cell Membrane?
Integral proteins such as receptors, channels, enzymes and cell attachment proteins.
Describe the polar and non polar regions of the Phospholipid
Polar Hydrophillic head region of chlorine and phosphate.
Non- Polar Hydrophobic fatty acid chain.
What are the small intracellular organs called?
Organelles
Name the Organelles found within a Eukaryotic Cell
Mitochondria, Rough ER, Smooth ER, Golgi apparatus, lysosomes and the Nucleus.
Whats is the Cytoskeleton?
A set of filamentous cytosolic Proteins. Which determines the shape and fluidity of the cells.
What are the Three main classes of filaments and what are the composed of?
Microfilaments - Composed of protein Actin.
Intermediate Filaments - Composed of 6 main proteins which vary
Microtubules - tubulin proteins
What are Microfilaments?
Composed of fine strands of the protein Actin. Have a Diameter of 7nm or 0.007µm
What are Intermediate Filaments?
Bind intracellular elements together and to the Plasmalemma. There are more than 50 types and vary depending on the proteins which they are composed of. Diameter of 10-15nm.
What are Microtubules?
They are composed of Alpha and Beta tubulin subunits. Originate from the centrosome in the centre of the cell. Diameter of around 25nm.
What are the Functions of Microtubules aside from structure?
They can help move things around within the cell. Dyen and kinesin attach and can move along while dragging associated organells by their membranes.
Can also help in production of spindle.
What is the Nucleus?
Contains genetic code for the cell.
An inner and outer nuclear membrane with a gap - perinuclear cistern.
where are mRNA and tRNA transcribed?
In the nucleus - rRNA is transcribed in the nucleolus
What are Ribosomes?
Production factory or making proteins.
What is the endoplasmic reticulum?
The ER forms a network of interconnecting membrane bound components in the cell.
What is the difference between the smooth and Rough ER?
The rough ER is studded with ribosomes and is the site of protein synthesis and initiation of glycoprotein formation.
The Sooth ER continues the processing of proteins from the RER and is the site of lipid synthesis.
What is the Golgi apparatus?
Composed of a group of flattened membrane bound cisternae this is where the produced components (macromolecules) from the SER are modified and packaged.
Where do the transport vesicles from the SER take the macromolecules?
The Golgi apparatus
What are mitochondria?
The powerhouse of the cell they generate ATP. Composed of inner and outer membrane, the inner is invaginated to increase surface area.
Where to reactions take place within the Mitochondria?
on the invaginated inner membrane.
What are intracellular junctions?
Specialised membrane structures which link individual cells into a functional unit.
What are the 3 main types of Intracellular Junctions?
Occluding Junctions, Anchoring Junctions, Communicating Junctions
What is an Occluding Junction? (aka zonula occludens)
An occluding junction prevents diffusion by linking cells to produce a diffusion barrier.
What is an Anchoring Junction?
Anchoring junctions provide mechanical strength, they link sub-membrane actin bundles of adjacent cells.
Desmosomes link submembrane intermediate filaments of adjacent cells.
What are Communicating Junctions?
Allow movement of molecules between cells. Often called gap junctions, Each junction is studded with pores (produced by connexion proteins).
Found in the epithelium, but also in smooth and cardiac muscle.
What is a Junctional Complex?
Close association of several types of junctions found in certain epithelial tissues.
Name ways in which material can move across the cell.
By Diffusion, Transport proteins (Pumps or channels) or by incorporation into vesicles (endocytosis, phagocytosis)
What is Endocytosis?
Material from extracellular space is incorporated into a cell. Cell membrane invaginates, fuses and the newly made endocytotic vesicle buds into the cell.
What is Exocytosis?
Material from intracellular space is expelled out of the cell. Vesicle secretes molecules to the extra cellular space.
What is Phagocytosis?
Bacterium binds to surface receptors triggering extensions of the cell to engulf it forming a phagosome. This binds with a lysosome which contains digestive enzymes creating a phagolysosome.
