LECTURE 3 Cells and Chromosomes Flashcards
All cells have
- DNA (genetic info)
- Ribosomes (make proteins)
Prokaryotes
—no nucleus
- Bacteria
- Archaea
Eukaryotes
Have nucleus and other organelles
Multicellular organisms (eukaryotes)
Every cell has the same DNA (information)
•Except?
red blood cells and gametes
Different cell types EXPRESS different genes
DIFFERENTIATION – cell is specialized
The Plasma Membrane
•Lipid bilayer with proteins and
carbohydrates
Selective Barrier
- Separates cell from the environment
- Lets some materials across to keep the cell functioning properly
- Similar structure for organelle
membranes
DNA + protein =
chromatin
Euchromatin=
- Loosely packed
- Interphase
- Active genes
Heterochromatin
- Tightly packed
- Metaphase
- Inactive genes
(Endoplasmic Reticulum)
Rough ER (RER)
- Bound ribosomes
- Synthesis of secreted proteins and glycoproteins
(Endoplasmic Reticulum)
Smooth ER (SER)
- Lipid Synthesis
- Membrane synthesis
Golgi Apparatus
- Polarized stack of membranes
- Enzymes modify proteins from ER
- Add & modify sugars
- Material moves between stacks via transport vesicles •Many final destinations
Protein synthesis occurs in different places Cytoplasmic proteins:
- Made of free ribosomes in the cytoplasm
- Proteins are soluble (hydrophilic)
Protein synthesis occurs in different places
Membrane proteins and secreted proteins:
- Made on ribosomes bound to the ER
- Sorted in the Golgi apparatus
- Membrane proteins are hydrophobic or amphipathic •Secreted proteins can be either hydrophilic or hydrophobic (or amphipathic!)
Lysosomes: Acidic organelles ?
Digest food & polymers to recycle monomers Phagocytosis and Autophagy
Mitochondria?
makes ATP (energy for the cell)
Sperm delivers…
DNA (genetic information) – the egg provides everything else
Cytoskeleton
Support for the cell
- Microtubules (tubulin)
- Microfilaments (actin)
- Intermediate Filaments (keratins)
- Other proteins link these structures together
Diploid and Haploid
Diploid cells contain two complete sets (2n) of chromosomes. Haploid cells have half the number of chromosomes (n) as diploid - i.e. a haploid cell contains only one complete set of chromosomes. Cell Division and Growth. Diploid cells reproduce by mitosis making daughter cells that are exact replicas.
Endosymbiosis
symbiosis in which one of the symbiotic organisms lives inside the other.
CELL STRUCTURES
Sandwich model
Difference between Nucleus and Nucleolus
Nucleus stores DNA;
Nucleolus makes
ribosomes
What does Ribosomes make?
Proteins
