Structures found in cells Flashcards
What is this?
Mitochondria is a cigar-shaped organelle dound in nearly all cells. It has a double membrane with innner membrane highly folded. (this is a cristae). It contains a fluid matrix. Also contains circular DNA and 70s ribosomes.
What is the mitochondrion’s function?
It’s the sight of aerobic respiration which produces ATP, an energy source for cells.
What is this?
The nucleus.
It has a double membrane (the nuclear envolope) which contains small holes (nuclear pores). Contains chromatin and the nucleolus.
What is the function of the nucleus?
Chromatin condenses to form chromosomes made of DNA. Genes are located of chromosomes and code for different proteins.
Nucleolus synthesises ribosomes (rRNA)
Pores in the nuclear envolope allow mRNA to pass out of the nucleus.
Nuclear envolope separates the DNA from the rest of the cellular contents.
What is this?
A series of membarne bound flattened sacs running through the cytoplasm.
The membrane of the rough ER are arranged in regular lines and are studded with ribosomes.
The membrane of the smooth ER are less organised and there are no ribosomes.
What is the ER’s function?
Transports substances (proteins and lipids) through the cytoplasm to the golgi body.
What is this?
Ribosome, a very small organelle not bounded by a membranes (80s). They are composed of 2-subunits and are found on the RER and free in the cytoplasm. They are made of rRNA (ribosomal RNA) and protein.
What is the function of the ribosomes?
They are the sight of protein synthesis.
What is this?
Choroplasts- the sight of photosynthesis. They trap light energy that is then used to produce carbohydrates. The pigment chlorophyll absorbs the light energy.
What is this?
A stack of flattened membrane bound sacs. Secretory vesicles and lysosomes bud off its edge.
What is the function of the golgi body?
Stores and chemically modifies substances such as proteins and prepare them for secretion from the cell.
Produces glycoproteins
Storage of lipids.
What is this?
Secretory vesicles
Membrane bound vesicles that are budded off the golgi body.
If they contain digestive enzymes then they are lysosomes.
If they contain products to be secreted from the cell then they are vesicles.
What’s the function of the secretory vesicles?
Lysosomes fuse with old organelles to dispose of them. The digestive enzymes they contain break down the organelle. Vesicles move to the cell membrane where they fuse with it and secrete their contents outside of the cell via exocytosis.
What is this?
Cell membrane is composed of a phospholipid bilayer with intrinsic and extrinsic proteins.
The membrane surrounds and contains the jelly-like cytoplasm in whihc organelles are suspended. many cellular reactions occur in the cytoplasm.
What’s the function ofthe cell membrane?
It is partially permeable and controls the movement of substances into and out of the cell. It maintains different concentration of substances inside and outside the cell. It also allows cell to cell identification.
What is this?
Composed of cellulose in plants, murein in bacterial cells and chitin in fungal cells. It exists outside of the cell membrane.
Pores called plasmodestmata perforate plant cell walls.
What is this?
Vacuole, surrounded by a single membrane, the tonoplast. Contains water and dissolved solutes.
Only in plant cells
Animal cells may have small vacuoles.
What is this?
Centrioles: a pair of tubular structures taht move to opposite ends of a cell during cell division.
DO NOT occur in plant cells (MTOC instead.)
