Chapter 3 Flashcards
What is the structure and function of the cell membrane?
- made from lipids and proteins
- regulates movement of substances in/out of cell
- receptor cells recognise and allow cells to respond to chemical signals like hormones
What are the properties of the nucleus?
- contains DNA and chromosomes
- site of DNA replication
- contains 1 or more nucleoli - to synthesise ribosomes
- surrounded in nuclear enevelope
What is the structure and function of the mitochondira?@
- site of aerobic respiration
- provides energy
- doubles membrane for larger DA for respiration
What is the structure and function of the chloroplasts?
PLANTS
- site of photosynthesis = in thylakoid membrance and grana
What is the structure and function of the golgi body?
- flattened sacs that produce vessicles (vessels that remove things from cell)
- processes and packages substances made by rough and smooth ER
What is the structure and function of lysosomes?
- types of golgi body
- produces digestive enzyme lysozymes to digest cells
What is the structure and function of the ribosomes?
- tiny organelles that float in cytoplasm and attach to rough ER
- where proteins are synthesised
What is the structure and function of the endoplasmic reticulum?
- membrane folds connected to nuclear enevelope
- spaces between folds filled with fluid to transport substances around cell
- SMOOTH = synthesise and process lipids
- ROUGH = studded in ribosomes to synthesise and transport proteins
What is the structure and function of the cell wall?
PLANTS
- made from cellulose
- supports plasma membrane
- maintains structure of plant cell
What is the structure and function of the vacuole?
PLANTS
- mature plants = larger
- filled with water, pigments and waste
- turgid = keeps cell supported
How are cells specialised?
- Cells specialised to become tissues
- tissues work together to perform function and make an organ
- organs work togther to produce organ systems
Give an example of specialised cells.
- Epithelial cells become epithelial tissues
- epithelial tissues work with glandular and muscular tissues to form stomach
- stomach part of digestive system
What is the structures in prokaryotes?
- plasmids
- flagella
- capsule
- small ribosomes
- no nucleus = circular DNA floats around cell
- cytoplasm = no membrane bound organelles
- cell wall = contains muren (glycoprotein)
What are the properties of an optical microscope?
- uses light to form an image
- max resolution of 0.2 micrometers
- max magnification of x1500
What are the properties of an electron microscope?
- uses electrons to form an image so higher res that optical
- max resolution of 0.0002 micrometers
- max magnification of x1500000
What is the formula for magnification?
magnification = size of observed image/size of real
What is the difference between resolution and magnification?
resolution = how detailed the image produced is -how microscope differentiates between to points close together magnification = how much bigger the object is made
How would you convert 1 micrometer to 1 mm?
divide the micrometer by 1000
What is the process of cell fractionation?
- put cut up tissue in cold, buffered, isotonic solution
- homogenise (blend)
- filter homogenate to remove debris
- put in centrifuge machine at low speed
- remove supernatant, decant and re-centrifuge at higher speed until desired organelle removed
What are the properties of a scanning electron microscope?
- scan a beam of electrons at specimen to knock of its own electrons which are gathered in a cathode ray to form an image
- shows surface of specimen
- used on thick specimen
- lower resolution that TEMs
What are the properties of transmission electron microscopes?
- uses electromagnets yo focus a beam of electrons which are transmitted through specimen
- denser parts absorb more electrons = darker
- higher resolution
- only used on thin specimens
What is the fluid mosaic model?
- called phosopholipid bilayer
- contains cholesterol to keep structure and stop membrane being too fluid
- glycoproteins and glycolipids recognise own/foreign cells
- small, non-polar pass easily
- large or polar molecules go through carrier/ channel proteins
What does isotonic mean?
same amount of water in and out of cell so no osmosis
What does hypertonic mean?
more water inside cell than out so water moves out = cell shrivels
