Cell Features Flashcards
Describe DNA in prokaryotes
- Short circular molecule of DNA, not associated with protein and found in cytoplasm
- Carries genetic code for proteins
Describe the cell wall in prokaryotes
- Contains murein, a glycoprotein, or peptidoglycan
- Prevents osmotic lysis. Rigid, for strengthening
Describe the cytoplasm in prokaryotes
- Solution where many dissolved molecules are found, no membrane bound organelles
- Site of many metabolic reactions
Describe the cell surface membrane in prokaryotes
- Controls passage of substances across exchange surfaces by passive or active transport
- Phospholipid bilayer with embedded proteins
Describe the ribosomes in prokaryotes
- Small ‘70S’ structures in cytoplasm
- Protein synthesis
Describe the flagellum in prokaryotes
- Thin rotating fibre
- Responsible for movement of cell
Describe the plasmids in prokaryotes
- One or more small loops of DNA that can replicate individually
- Can pass on genetic information via conjugation to other bacteria
Describe the capsule in prokaryotes
- Extra slime layer outside cell wall
- Protects from dessication, phagocytosis and some pathogens
Describe the plasma membrane in eukaryotes
- Made of phospholipid bilayer and embedded proteins on surface of cell and some organelles
- Selectively permeable, allows cell identification
Describe the nucleus in eukaryotes
Contains chromosomes which are long linear DNA molecules, surrounded by nuclear envelope, containing some nucleoli
- Contains genetic code
- Nucleoli manufacture proteins
Describe the mitochondria in eukaryotes
- Surrounded by 2 membranes, inner membrane folds forming cristae
- Fluid inside called matrix
- Contains circular DNA
- Produces ATP from aerobic respiration
Describe the Rough Endoplasmic Reticulum in eukaryotes
- Series of tubes in cytoplasm, with many ribosomes attached
- Synthesis and transport of proteins through cytoplasm
Describe the ribosomes in eukaryotes
- Small ‘80S’ organelles made up of rNA and proteins
- Protein synthesis
Describe the smooth endoplasmic reticulum in eukaryotes
- A series of tubes in cytoplasm of cell, with no ribosomes attached
- Synthesises and transports lipids
Describe the golgi apparatus in eukaryotes
- Stack of flattened sacs with vesicles continually budding off
- Processes and modifies proteins and sends them off in vesicles
- Forms lysosomes
Describe the lysosomes in eukaryotes
- Golgi vesicle containing hydrolytic enzymes known as lysozymes
- Digests unwanted material inside the cell
Describe the cell wall in plants
- Made of cellulose providing high tensile strength preventing osmotic lysis
- Cell walls in fungi are made from chitin
Describe the vacuole in plants
- Filled with cell sap
- Provides rigidity
Describe the chloroplasts in plants
- Site of photosynthesis
Describe the envelope in chloroplasts
- Double membrane surrounding the organelle
Describe the granum in chloroplasts
- Stack of membrane bound discs called thylakoids which contain chlorophyll
- Provides a large surface area to maximise rate of photosynthesis
Describe the stroma in chloroplasts
- Contains enzymes needed for photosynthesis and stores starch grains
- Almost like a cytoplasm
Describe the ribosomes in eukaryotes
- Small ‘70S’ organelles
Describe the DNA in chloroplasts
- Short circular and not associated with proteins
Describe Viruses
- Acellular
- Non-living
- Attach to a host cell and uses its systems to replicate
Descrive the features of a virus
- Genetic material is either DNA or rNa
- Capsid is a protein coat
- Attachment proteins allow the virus to attach to a host cell (complementary to receptors on host cell)
What is rNA
Single stranded DNA with different bases. Is not permanent
