2.1-2.2 - Cell structure & function Flashcards
Prokaryotic cells location
bacteria and Archaea.
Prokaryotic cell structure
- No nucleus
- DNA located in nucleoid
- No membrane-bound organelles.
- Cytoplasm bound by plasma membrane.
Eukaryotic cells
- DNA in nucleus bound by a membranous nuclear envelope.
- Cytoplasm between plasma membrane & nucleus
*Larger than prokaryotic cells.
Plasma membrane
Selective barrier that allows passage of oxygen, nutrients, & waste
Plasma membrane composition
- Double membrane of phospholipids
- Proteins and carbohydrate side chains
- Hydrophilic top & bottom
- Hydrophobic middle
Nucleus
- Controls genes and directs other parts of the cell.
Endoplasmic reticulum
Composed of smooth & rough ER.
Provides mechanical support
Smooth ER
- Makes lipids and breaks down toxins.
- Does not have ribosomes.
Rough ER
- Contains ribosomes that synthesize proteins.
Ribosomes
- Composed of proteins and ribosomal DNA
- mRNA goes through the middle, translates messages to a protein in the ER.
Golgi complex
Takes proteins & lipids produced in the ER and transfers it to different parts of the cell.
Lysosome
- Full of digestive enzymes.
- Breaks down viruses by fusing with them and creating a phagosome.
- Dissolves malfunctioning mitochondria.
- Can kill cells.
Mitochondria
- Produces ATP
- Cell where cellular respiration occurs.
Mitochondria composition
- Phospholipid bilayer with embedded proteins
- Smooth outer layer, inner layer with cristae.
- Divided into 2 internal compartments by inner membrane
- Intermembrane space
Inner region between inner and outer membranes.
- Mitochondrial matrix
- Contains enzymes, mitochondrial DNA, & ribosomes
- Enzymes catalyze cellular respiration
- Enclosed by inner membrane
How does cristae enhance cellular respiration?
By giving mitochondria large surface area.
What is ATP responsible for?
- Active transport
- Muscle contraction
ATP composition
- 3 phosphates
- ribose sugar
- adenine base
How does ATP operate?
- ATP is hydrolyzed & loses a phosphate
- Turns into ADP, cellular respiration replaces phosphate
- Lost phosphate is transferred to embedded protein.
- Exergonic reaction
Why does ATP lose a phosphate?
Phosphates are less stable in 3’s, are more stable in 2’s.
What happens to the embedded protein after the phosphate enters it?
Protein becomes more reactive & less stable.
*Phosphorylated intermediate state.
Hydrolytic enzymes
- Important in intracellular digestion
- recycling of cell’s organic materials
- programmed cell death (apoptosis).
Vacuoles
- Storage and release of macromolecules & waste
- aids in water retention in plants for turgor pressure.