Unit 3 - Cell Structure Flashcards
Name the organelles
Name the 6 principles of Cell Theory
- all known living things are made up of cells. 2. the cell is structural & functional unit of all living things. 3. all cells come from pre-existing cells by division. 4. cells contains hereditary information which is passed from cell to cell during cell division. 5. all cells are basically the same in chemical composition. 6. all energy flow (metabolism & biochemistry) of life occurs within cells.
What tool allows us to study cells?
The microscope
Name the 3 main modern microscopes
- Light Microcscope 2. Scanning Electron Microscope 3. Transmission Electron Microscope
Light Microscope Properties
resolution of 0.2 μm
Scanning Electron Microscope Properties
Resolution of 10 nm, produces a 3-D micrograph image
Transmission Microscope Properties
Resolution of 0.5 nm, produces a 2-D cut through micrograph
What 4 properties to Eukaryotic and Prokaryotic cells share?
- DNA 2. Cell membrane 3. Ribosomes 4. Site of metabolism
What are the differences between Eukaryotic and Prokaryotic cells?
The ability of a cell to bring in enough nutrients depends on what ratio?
The surface area : volume ratio
What 2 regions are cells divided into?
- Nucleus 2. Cytosplasm
Describe the nucleus
Contains the genetic material of the cell, is surrounded by the nuclear membrane
Describe the cytoplasm
Contains the organelles and has cytosol (made of water, ions, organic monomers and polymers)
What forms the outer barrier of a cell?
The plasma membrane (cell membrane)
What is the Fluid Mosaic Model? What does it say about the plasma membrane?
It’s the currently accepted description of the plasma membrane. It states that the cell membrane consists of a phospholipid bilayer with embedded proteins
What are the 5 functions of the plasma membrane?
- Separates the extracellular fluid from the intracellular fluid 2. Regulates the passage of materials into and out of the cell / organelle 3. Communicates (detects chemical signals from other cells, displays antigens) 4. Forms junctions (holds cells together) 5. Anchors proteins
Whats the function of cell junctions?
Hold together groups of cells and provide means for cell communication
What are the 4 types of cell junctions?
– Desmosomes – Tight junctions – Gap junctions – Plasmodesmata
Desmosomes
Strong, flexible attachment EX. Skin, intestine, urinary bladder
Tight Junctions
Provide leak proof junctions EX. Urinary bladder, blood vessels
Gap Junctions
Form communication channels between cells Ex. Heart muscle cells
Plasmodesmata
Connect the insides of adjacent plant cells
What is the nucleus bound by? (Surrounded by, protected by)
The nuclear envelope
What does the nuclear envelope consist of?
A phospholipid bilayer and pores that regulate transport
What does the nucleus do?
Controls cell function and genetics (controls production of all proteins)
What proteins is DNA associated with and what do they form?
Histone proteins, form chromatin
What is the nucleolus responsible for?
The synthesis of ribosomal DNA
What are ribosomes composed of?
Ribosomal RNA and protein
Free ribosomes are usually found in groups called ______ and produce proteins for _______ use
Polysomes, internal
Ribosomes attached to the _________ usually make proteins for ________
Endoplasmic Reticulum, export
What are the sites of protein synthesis?
Ribosomes
Ribosomes consist of one ____ unit and one _____ unit
Small, large.
What is the Endoplasmic Reticulum?
A membranous system of tubular canals beginning at the nucleus and branching out into the cytoplasm
What are the 2 functions of the E.R?
- transports chemicals between cells and within cells 2. provides a large surface area for the organization of chemical reactions and synthesis
What are the two types of Endoplasmic Reticulums?
Rough E.R Smooth E.R
Rough Endoplasmic Reticulum
Contains ribosomes Transports and modifies proteins produced by the ribosomes
Smooth Endoplasmic Reticulum
No ribosomes Produces lipids and carbohydrates Detoxifies toxins Abundant in cells of the liver, testes, etc.
Describe the Golgi Apparatus
Consists of membranous sacs stacked like pancakes
What are the 4 functions of the Golgi Apparatus?
- Processes material synthesized by the E.R 2. Packages the material and provides the “address label” 3. Distributes material in sacs called vesicles (some for inside, others for outside the cell) 4. Synthesis and transport of polysaccharides
What are vacuoles and vesicles?
Organelles which function in the storage and/or transport of substances within the cell
What’s the difference between vacuoles and vesicles?
Vacuoles are large, vesicles are small
What does the central vacuole in plants do?
Provides structural support
How are vacuoles and vesicles formed?
The infolding (pinching off) of a membrane
What’s a lysosome?
A special type of vesicles formed by the Golgi Apparatus that contain Hydrolytic enzymes
What are the 3 functions of lysosomes?
- Digestion of macromolecules taken in by endocytosis 2. Autodigestion of damaged or worn cell parts 3. “Suicide bag” for the destruction of the entire cell
What is the mitochondria and what is it the site for?
The power-house of the cell, cellular respiration
How many membranes make up the mitochondria?
2
Describe the inner membrane of the mitochondria
The inner membrane contains many folds called Cristae which contain the enzymes necessary for the production of ATP
Which 2 organelles contains their own DNA and ribosomes, and are also self-replicating?
The Mitochondria and Chloroplasts
Where are chloroplasts found
Green plants only
What do chloroplasts do?
They capture light energy for photosynthesis
