Cells Daisy Flashcards
(42 cards)
Evidence for Cell Theory?
- Invention of microscopes
* Mould growth in oxygen
What are the points of Cell Theory?
- Living organisms are composed of cells
- Cells are the smallest unit of life
- Cells come from pre-existing cells
Size of a cell membrane?
7nm
Size of a virus?
30 - 120nm
Size of a bacterium?
2 um
Equation for surface area to volume ratio?
Surface area / volume ratio
What is a specialised cell?
A cell that has been specifically designed to carry out a certain function to allow the multicellular organism to survive. They do this by switching some genes on/off.
What is is a stem cell?
A cell that can specialise into anything
Name one therapeutic use of a stem cell
- Grafting new skin cells in burn victims
- Replacing nerve cells in spinal injuries
- Bone marrow transplants in chemotherapy
What is a prokaryotic cell?
Cells that are made of one cell
What is binary fission?
How bacterial (prokaryotic) cells divide
What is a eukaryotic cell?
Cells that are dependent on more than one of itself to survive.
Differences between eukaryotic and prokaryotic cells?
- DNA associated with proteins vs naked DNA
- DNA in nuclear envelope vs DNA in cytoplasm
- mitochondria vs no mitochondria
- eukaryotic cells have internal membranes that compartmentalise their functions
Differences between plant and animal cells?
- Plant cells have chloroplasts
- Plant cells have a cell wall
- Plant cells have a vacuole
- Plant cells have a more structured shape
Two roles of extracellular components?
- Plant cell wall gives it structure and prevents it from bursting under high pressure
- Animal cell glycoproteins are involved in the support, movement and adhesion of the cell
How do the hydrophilic and hydrophobic properties of phospholipids maintain the structure of cell membranes?
Keeps it in a fluid state which allows the cell to change it’s shape easily. Hydrophilics face the water and hydrophobics face away from the water to keep structure.
Functions of membrane proteins?
- Hormone binding sites,
- Electron carriers
- Pumps for active transport
- Channels for passive transport
- Enzymes
Define diffusion
The movement of particles from an area of high concentration to an area of low concentration
Define osmosis
The diffusion across water from an area of high concentration to an area of low concentration through a partially permeable membrane
Define simple diffusion
When a substance passes through a membrane without the aid of an intermediary such as a integral membrane protein.
Define facilitated diffusion
Allows substances to cross the cell membranes by using transport proteins. The carrier proteins bond to these substances, which in turn allows them to change shape.
Explain the role of protein pumps and ATP in active transport across membranes
the movement of substances through the membrane using energy from ATP. substances can be moved against the concentration. The cell membrane has protein pumps embedded it which are used to move substances across by using ATP. The cell can control what comes in and what goes out.
How are vessels used to transport materials within a cell between the rough endoplasmic reticulum, Golgi apparatus and plasma membrane?
Vesicles carrying the protein bud off the rough endoplasmic reticulum and are transported to the Golgi apparatus to be further modified. After this the vesicles carrying the protein bud off the Golgi apparatus and carry the protein to the plasma membrane. Here the vesicles fuse with the membrane, expelling the modified proteins outside the cell. The membrane then goes back to its original state. This is a process called exocytosis.
Define endocytosis
The taking in of matter by a living cell by turning its membrane inside out to form a vacuole.
