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.
What are within chloroplasts?
Thylakoids and stroma
How are thylakoids organized?
In stacks called grana
What reactions occur in the grana?
Light-dependent reactions of photosynthesis
What is stroma?
Fluid within the inner chloroplast membrane and outside the thylakoid.
What reactions occur in the stroma?
Carbon-fixation reactions of photosynthesis
(Calvin-Benson cycle)
What are the reactions that occur in the mitochondria?
- Krebs cycle occurs in the matrix
- electron transport & ATP synthesis occur in the inner mitochondrial membrane.
