Cell Structure Flashcards
Cytoplasm
term used for the cytosol (fluid) plus the organelles suspended within the cytosol.
Cytosol (intracellular fluid)
fluid (solvent) within which all the other cell organelles float. The cytosol is mostly water but has solutes dissolved and suspended in it.
Organelles
metabolic machinery of the cell. These are membranous structures with specialised functions.
Inclusions
These may be present depending on cell type. Examples of inclusions are stored nutrients such as lipid in fat cells, and pigment granules in some skin cells.
Plasma Membrane
A double layer of phospholipids with hydrophilic heads and hydrophobic tails, bound with proteins, cholesterol and carbohydrates.
Phospholipid
Bilayer of lipids
Hydrophilic
Water loving and polar
Hydrophobic
Water hating and non-polar
Functions of the Plasma Membrane
- Transport
- Enzymatic activity
- Signal transduction
- Cell to cell recognition
- Intercellular joining
- Attachment to the cytoskeleton ECM
Mitochondria
Double membraned cristae that create energy (ATP) to function cells
Cristae
Double membrane that is folded with the inner membrane being smooth.
ATP
Adenosine triphosphate is an energy carrying molecule that is used in cells that release quick energy.
ADP
Adenosine diphosphate is an energy carrying molecule after ATP has been broken down and is a low energy molecule.
Centrosome
A area where two groups of microtubules (centrioles) are found.
Golgi Apparatus
A membranous structure with one membrane that it flat and packages and modifies proteins and lipids to transport them to other cells.
Vacuoles
Parts of golgi apparatus that have broken off and play a role in intracellular digestion and the release of cellular waste.
Lysosomes
Contains enzymes necessary for intracellular digestion.
Peroxisomes
Enzymes with their main function to break down hydrogen peroxide into water and oxygen.
Ribosomes
Small round structures that either float around in the cytosol or attached to the endoplasmic reticulum and synthesis proteins
Smooth Endoplasmic Reticulum
The smooth endoplasmic reticulum (ER) is a continuation of the outer nuclear membrane and is a vast network of membranous vesicles and tubules. It is called smooth because it appears smooth when looking through an electron microscope.
The functions include lipid and steroid hormone synthesis, breakdown of lipid-soluble toxins in liver cells, and control of calcium in muscle cell for contraction.
Rough Endoplasmic Reticulum
Rough endoplasmic reticulum (ER) appears uneven under the electron microscope because of the numerous ribosomes on the surface.
Proteins synthesized by the ribosomes are collected in the rough endoplasmic reticulum and are then transported throughout the cell.
Cytoskeleton
consists of microtubules and microfilamants which help to maintain cell shape. Some cells have hair-like projections from the plasma membrane with microtubules inside them. Another function of the cytoskeleton is cell motility. This includes the internal movement of cell organelles, cell division and muscle fiber contraction, as well as the locomotion of some cells eg sperm.
Nucleus
surrounded by a double membrane (envelope) with large pores which allows for communication with the surrounding cytosol. Inside the nucleus is nuclear chromatin, the entire genetic material in a human. The nucleolus is a big structure inside the nucleus which produces ribosomes. The ribosomes then move out of the nucleus into the cytosol where some attach to the endoplasmic reticulum.
