Cell Structure and Transport Flashcards
What is the maximum resolution of the light microscope and the electron microscope?
Light = 200nm Electron = 0.1nm
What is the maximum magnification of the light, SEM and TEM microscopes?
Light = x1500 SEM = x100000 TEM = x500000
Actual Size = ?
Image Size/Magnification
Magnification = ?
Image Size/Actual Size
What is resolution?
The ability to distinguish between 2 separate points clearly.
What is magnification?
The state of something being magnified or represented by an amplified image.
Outline the roles of cytoskeleton?
- Maintains the shape of the cell
- Allows movement of organelles
- Supports the cell
What are the role of vesicles?
Transport many different materials around the cell.
Structure of nucleus?
- Surrounded by nuclear envelope
- Nuclear pores in the nuclear envelope
- Nucleolus in the nucleus
- Has chromatin
What is the role of nucleus?
- Houses genetic info
- Contains chromatin that condenses during mitosis
- Nucleolus makes RNA and ribosomes
Structure of Rough Endoplasmic Reticulum?
- Flattened sacs called cisternae
- Joined to the outer nuclear membrane
- Littered with ribosomes that make proteins.
Structure of Smooth Endoplasmic Reticulum?
Same as Rough Endoplasmic Reticulum only without ribosomes.
What is the role of Smooth Endoplasmic Reticulum?
Involved in making lipids that the cell needs.
Structure of Golgi body?
Flat membrane-bound sacs(stacked)
Role of Golgi body?
Modification of proteins and transport of said proteins in vesicles.
Structure of mitochondria?
2 membranes separated by fluid filled space.
Inner membrane is highly folded to form cristae.
Central part is called matrix.
Role of mitochondria?
Produces ATP.
Structure of chloroplast?
2 membrane separated by fluid filled space.
Inner membrane is continuous, containing flattened membrane sacs called thylakoids(stack=granum/grana)
Role of chloroplast?
Site of photosynthesis.
Structure of lysosomes?
Single membrane, spherical sacs.
Role of lysosomes?
Contain powerful digestive enzymes, used to break down foreign objects/bacteria etc.
Where are ribosomes located?
Some are free in cell and some bound to rough endoplasmic reticulum.
Role of ribosomes?
Site of protein synthesis.
Structure of centrioles?
Small tubes of protein fibers, pair of them next to the nucleus.
Role of centrioles?
Take part in cell division, form spindle fibers that move chromosomes during anaphase.
Process of protein synthesis?
- mRNA(contain genetic code)
- Exits the nucleus, moving into the cytoplasm.
- mRNA is translated, organised by the ribosomes
- Assembled protein leaves the ribosome in a vesicle, where it may leave the cell or be used in the cell.
What are the role of membranes?
- Separating cell contents from the outside environment
- Separate the cell components from cytoplasm
- Cell recognition and signalling
- Regulating the transport of materials into/out of the cell.
Outline the structure of a phospholipid membrane.
- Hydrophilic head facing outwards.
- Hydrophobic tails facing inwards.
- Channel proteins allow quick movement of substances through the membrane
- Carrier proteins actively move substances across the membrane
- Glycoproteins/glycolipids:receptor sites.
What is cell signalling?
The communication between cells using hormones and complimentary receptor site.
What is diffusion?
Movement of molecules down a concentration gradient.
high conc. -> low conc.
What is active transport?
Movement of molecules against its concentration gradient with the use of energy.
What affects the rate of diffusion?
- Temperature
- Concentration gradient
- Distance
- Size of molecules
- Surface area
Outline facilitated diffusion using channel proteins.
It is a passive process which allows the transport of ions through the cell surface membrane.
Outline facilitated diffusion using carrier proteins.
It is a passive process which transports larger molecules through the cell surface membrane.
Outline bulk transport.
- Endocytosis(into the cell)
- Exocytosis(out of the cell)
- Requires ATP
Passive processes?
- Diffusion
- Facilitated diffusion
- Osmosis
Active processes?
- Active transport
- Bulk transport
What is osmosis?
Movement of water down its water potential gradient across a partially permeable membrane.
What happens to animal cells in a solution with high water potential?
- Cell swells as water moves down the gradient and fills the cell
- Animal cell bursts as it does not have cell wall to withstand the pressure.
What happens to plant cell in a solution with high water potential?
- Cell swells as water moves down the gradient and fills the cell
- Plant cell becomes turgid due to cell wall that prevents the cell from bursting
What happens to animal cells in a solution with low water potential?
-Cell shrinks and membrane shrivels up.
What happens to plant cell in a solution with low water potential?
-Cell shrinks and membrane will pull away from cell wall.
Why do multi-cellular organisms need transport systems?
- Small SA/Vol ratio
- Not all cells in contact with external medium.
- Tissues, organs are created to allow delivery of oxygen and removal of carbon dioxide.
What is differentiation?
When a cell takes on a particular role/function.
How can cells adapt to become differentiated?
- Increase the number of certain organelles within the cell.
- Change the shape of the cell.
What is tissue?
Collection of cells working together to perform a common function.
What is organ?
Collection of tissues working together to perform a particular function.
What is organ system?
Number of organs working together to perform an overall function.
Outline the xylem tissue structure.
- Parenchyma cells and fibres
- Walls reinforced with lignin
- Sunken pits where lignin is absent to allow water molecules to move into live tissue cells around the xylem
Outline the phloem tissue structure.
- Sieve tubes and companion cells.
- Companion cell is very metabolically active
Give 2 examples of epithelial tissues.
- Squamous epithelial
- Ciliated epithelial
Give 2 examples of connective tissues.
- Cartilage
- Bone & blood
