Cells as the Basis of Life Flashcards
Year 11 Module 1
What is the difference between prokaryotic and eukaryotic cells?
Prokaryotes:
* small
* simple structure
* no membrane-bound organelles
* no nuclear membrane
* have plasmids (small accesory chromosomes)
* nucleoid region - circular DNA
* often have a capsule
* often have flagella or pili
* cannot be multicellular
Eukaryotes:
* cellular membrane & cytoplasm
* nucleus containing linear DNA
* membrane-bound organelles and vesicles
* larger
* complex stucture
* can be unicellular or multicellular
What kingdom is prokaryotic?
monera (bacteria)
What kingdoms are eukaryotic?
- plants
- animals
- fungi
- protists
Why are plasma membranes fluid?
they can move/flow due to phospholipid stucture and lipid bilayer
What is the structure of phospholipids?
Hydrophilic phosphate head and hydrophobic fatty acid tail
What is the difference between saturated and unsaturated phospholipids?
Unsaturated lipids have a ‘kink’ in the tail and cannot stack neatly together so they are more fluid
What is the function of a plasma membrane?
- keeps cell separate from outside
- selectively permeable - controls what goes in & out of cell
- cell-cell and cell-external communication
- stuctural support
What are some adaptations of plasma membranes?
- strong for support, but flexible to allow growth & movement
- self-sealing so cell can divide without bursting
- antigens on surface to recognise other cells
- receptor sites for hormones & neurotransmitters
What are carrier proteins in the plasma membrane?
proteins that bind to specific molecules to transport them across the membrane
What are channel proteins in the plasma membrane?
proteins that act as a pore through which molecules can diffuse into the membrane
Which molecules can diffuse through the plasma membrane on their own?
- hydrophobic molecules
- small uncharged molecules (oxygen and CO2)
- small polar molecules (water)
Which molecules can diffuse through the membrane via channel proteins?
- charged or large molecules
- small ions
- water
Which molecules must be transported across the membrane via carrier proteins?
- sugars
- amino acids
- nucleosides
What does cholesterol do in the plasma membrane?
regulates fluidity, thickness, water penetration, and structure of lipid bilayer
What do carbohydrate chains do in the plasma membrane?
- cell binding
- hormone reception
- nutrient breakdown
- cell recognition
- cell communication
What does the mitochondria do?
produces cell energy via cell respiration
What do chloroplasts do?
contain chlorophyll which convert sunlight energy into glucose by photosynthesis
What does the rough endoplasmic reticulum do?
- covered in ribosomes that produce proteins
- transports proteins after production
What does the smooth endoplasmic reticulum do?
- depends on type of cell
- can include producing lipids and hormones
What does the golgi body do?
stack of membrane-bound vesicles that package proteins and other molecules for transport
What do lysosomes do?
- contain enzymes to aid digestion
- produce enzymes involved in immune response
What does the vacuole do?
- store nutrients and waste
- collect water to provide rigidity in plants
- larger in plants than animals
What does the ribosome do?
- contains RNA and proteins
- makes proteins
What is passive transport?
the movement of particles without the need for added energy (ATP)