Prokaryotes: Structure & Function (BE #2) Flashcards
Prokaryotic cells
- lack a membrane bound nucleus and membrane-bound organelles
- have one circular chromosome
- have a cell wall made of peptidoglycan
- much smaller than eukaryotic cell
Eukaryotic cell
- has a membrane-bound nucleus & organelles
- may or may not have a cell wall
- includes:
- fungi
- plants
- protistans
- animals
Viruses
- considered acellular
- not prokaryotic or eukaryotic
Which of the following groups or organisms have cells with cell walls?
What are the primary compounds found in their cells’ walls?
- animals
- plants
- protistans
- bacteria
- viruses
animals - no cell wall
plants - yes, cell wall - cellulose
protistans - plant-like ones (algae) - yes; other cells don’t have a cell wall
bacteria - yes, cell wall - made of peptidoglycan
viruses - acellular, so no cell wall
What are the advantages to having a small cell size?
Allows cells to grow faster & multiply more rapidly than eukaryotic cells.
It’s easier to meet their modest nutritional needs.
Why is it important to know the differences between prokaryotes and eukaryotes?
it allows us to control disease causing bacteria without harming our own cellls.
lysing
too much water in the cell will cause it to lyse
crenate
the loss of too much water will cause the cell to shrink or crenate
Which group of bacteria lack a cell wall?
mycoplasmas
How do mycoplasmas keep from lysing?
- they actively pump sodium ions out of the cell
- they have cholesterol within their plasma membrane to help keep it rigid.
The plasma membrane is composed primarily of ____________ molecules.
phospholipid
The plasma membrane is “semipermeable.” Explain.
Only some molecules are allowed into the cell.
Name one structure that allows the membrane to behave more like a fluid.
- kinked fatty acid tails
- shorter tails keep tails from packing
- cholesterol and proteins also create space
What is the major function of integral proteins in the plasma membrane?
transport proteins
Name 2 major types of transport proteins
- carrier protein
- channel protein
What is a major function of peripheral proteins in the plasma membrane?
Act as enzymes (catalyze chemical reactions)
Name 3 types of passive transport
- diffusion
- facilitated diffusion
- osmosis
How do molecules move from a high to a low concentration?
Their own kinetic energy causes them to move & they bump into one another (diffusion).