Membranes, Proteins, & Communication
Which proteins on bacterial surfaces serve as cell-surface identity markers recognized by immune cells? What protein function is this example of?
Bacterial surface antigens (proteins). This is an example of the Cell-surface identity marker function of membrane proteins.
How is DNA arranged in prokaryotes compared to eukaryotes?
Prokaryotes have circular DNA without histones; eukaryotes have linear DNA packaged with histones.
What molecule is the bacterial cell wall made of? What is the key difference between Gram + and Gram - bacteria?
Peptidoglycan.
Gram +: thick peptidoglycan layer, stains purple
Gram -: thin peptidoglycan layer, additional outer protective membrane layer, stains pink
What do chloroplasts and mitochondria have in common?
- Both have their own DNA
- Both used to be independent, metabolizing, prehistoric organisms of their own (endosymbiosis theory)
- Both are membrane-bound organelles
- Both found in plants
What organelle contains digestive enzymes for breaking down macromolecules, cell wastes, and pathogens?
lysosomes
Carrier proteins exhibit what kind of binding model to transport molecules?
A “lock and key” model, based on specificity to a particular agent.
How far apart must two objects be for the naked eye to distinguish them as two separate objects.
Objects must be 100 μm apart
What is the name of the structural cell component unique to eukaryotic cells only?
Cytoskeleton
Name the three main types of cytoskeletal fibers and their functions
Microfilaments/actin (cellular movement), microtubules (transport and organizing), and intermediate filaments (maintains structure of cell).
Which plant organelle stores water and other molecules, often occupying most of the cell’s volume?
The central vacuole.
Name the six main functions of membrane proteins
Transporter, enzyme, cell-surface receptor, cell-surface identity marker, cell-to-cell adhesion, attachment to cytoskeleton.
What is Resolution?
The minimum distance two points can be apart and
still be distinguished as two separate points
Which three domains consist of eukaryotic organisms?
Animals, plants, fungi
What arrangement of microtubules is found in eukaryotic cilia and flagella?
9+2 arrangement
What is the primary function of the nucleolus?
Producing and assembling ribosomes.
what does MHC stand for and what do MHC proteins do?
MHC = major histocompatibility complex
Play a role in recognition of “self” and “nonself” cells by the immune system.
What does the cell theory state about the origin of all cells?
All cells arise from pre-existing cells.
What structure allows bacteria to attach to a host cell and transfer DNA during conjugation?
Pili (aka fimbriae)
What is the function of centrioles in animal cells?
Organizing microtubules and aiding in spindle formation during cell division.
Extracellular Matrix (ECM)
What is the endomembrane system? Is this present in prokaryotes or eukaryotes?
Series of membranes throughout the cytoplasm:
- Divides cell into compartments where different cellular functions occur
- modify, package, and transport lipids and proteins
- eukaryotes only
Why are most cells small in size?
To maintain a high surface area-to-volume ratio for efficient transport and communication.
What is the hallmark of eukaryotic cells and how is this achieved?
Hallmark: Compartmentalization
Achieved through membrane-bound organelles and
endomembrane system
What are the two components of the nuclear envelope?
1) Nuclear pores (control movement in and out of nucleus)
2) two phospholipid bilayers
What are the three functions of a cell wall?
Protect the cell, maintain its shape, and prevent excessive uptake or loss of water