Lecture 7 Flashcards
(28 cards)
Internal organization of the cell: Prokaryotic
Absence of a nucleus, absence of discrete organelles and they’re bacteria and archaea.
Internal organization of the cell: Eukaryotic
Presence of a nucleus, presence of discrete organelles and they’re animals and protists.
Prokaryotic cells: Nucleoid
Within the cell’s interior. It’s a discrete concentration of DNA.
Prokaryotic cells: Plasmids
Small circular molecules of DNA. These molecules carry a smaller amount of genes.
Prokaryotic cells: Pili
Singular pilus. Plural pili. It’s threadlike and hollow. They’re structures that extend from one bacterial cell to another, which allow the transfer of plasmids.
Expand on eukaryotic cells.
Animal cells & plants differ in different ways. However, they do share certain similarities. They both have a nucleus, organelles and the same size. They are highly structured and are divided into multiple internal compartments.
Eukaryotic cells: Cytosol
Aka cytoplasmic matrix. It is the liquid found inside cells
Eukaryotic cells: Cytoplasm
It’s the area within the plasma membrane. It comprises cytosol, mitochondria, plastids and other organelles (but not their internal fluids & structures). It does NOT comprise the nucleus.
Eukaryotic cells: Endomembrane system
These are the organelles inside the cell that are not distinct. They communicate with each other by membrane “bridges” or by the budding of vesicles.
Eukaryotic cells: What are vesicles?
Small membrane enclosed sacs.
Eukaryotic cells: Endomembrane system, what does it include?
Nuclear envelope, ER, golgi apparatus, plasma membrane and vesicles.
Eukaryotic cells: Endomembrane system: Nucleus
Stores DNA
Eukaryotic cells: Endomembrane system: Nuclear envelope
It defines the boundary of the nucleus. It consists of two membranes (inner & outer). Each membrane is a lipid bilayer with associated proteins.
Eukaryotic cells: Endomembrane system: Nuclear pores
It acts as gateways that allows molecules to enter and leave the nucleus.
Eukaryotic cells: Endomembrane system: Nucleolus
It appears as a mass of densely stained granules and fibres. It is where rRNA is synthesized. It is also where large and small ribosomal subunits are assembled.
Eukaryotic cells: Endomembrane system: Ribosomes
They’re made of rRNA and proteins which form large and small subunits. It is where protein synthesis happens (which is when amino acids are assembled into polypeptides).
Eukaryotic cells: Endomembrane system: ribosomes: free ribosomes
They’re found floating in the cytosol, synthesized proteins that do not leave the inside of the cell.
Eukaryotic cells: Endomembrane system: ribosomes: bound ribosomes
They’re attached to the ER membrane, they’re synthesized proteins that are secreted or they’re components of the plasma membrane.
Eukaryotic cells: Endomembrane system: ER
It’s continuous with the nuclear envelope. It makes up >50% of total membrane in many eukaryotic cells. There are two regions: smooth or rough ER.
Eukaryotic cells: Endomembrane system: ER: rough ER
It’s studded with ribosomes on the surface of the membrane. It’s where proteins are synthesized that are going to be secreted. It’s also where membranes are synthesized.
Eukaryotic cells: Endomembrane system: ER: smooth ER
It’s outer surface lacks ribosomes. It functions in diverse metabolic processes, which change from cell type to cell type. It’s synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons, and storage of calcium ions.
Eukaryotic cells: Endomembrane system: golgi apparatus
It looks like a series of flattened-membrane sacs. This is called cisternae. Stacked cisternae are surrounded by many small vesicles. It is not continuous with the ER, its is own thing. It’s the next place that most vesicles go that bud from the ER.
Eukaryotic cells: Endomembrane system: What are the 3 main functions of golgi apparatus?
- It further modifies the lipids and proteins that are made by the ER
- It acts as a sorting station
- It’s where carbohydrates synthesize
Eukaryotic cells: Endomembrane system: lysosomes
It is specialized vesicles that come from the golgi. It’s purpose is for intracellular digestion: degraded, damaged or unneeded macromolecules, bacteria or other smaller organisms that have been engulfed. Macromolecules consists of proteins, nucleic acids, lipids and complex carbs. The membrane-bounds-proton-pumps keep the internal environment at an acidic pH of around 5 (optimal pH for degrading enzymes).
