Chapter Five Flashcards
4 tenants of cell theory
- cells are the fundamental units of life
- All organisms are composed of cell
- All cells come from pre-existing cells
- Modern cells evolved from a common ancestor
What does cell theory lead us to know?
Functions of all cells are similar
Life is continuous
Origin of life had to do with cells
Why are cells the fundamental units of life?
They are able of independent existence, and can carry out the vital functions of life.
How do Prokaryotes differ from Eukaryotes?
prokaryotes don’t have nucleus or membrane enclosed organelles
Eukaryotes are 10x larger than prokaryotes
prokaryotes are always single celled, while eukaryotes can be single or multi
what is the cell wall and what does it do?
rigid, outside of the cell membrane
determines the cell’s shape and provides support
{(bacterial cell walls contain peptidoglycan
further outside that is the outer-membrane)
only in prokaryotes}
give definition of a membrane, its composition, it’s function, and its characteristics.
It is the boundary of the cell, and it is composed of a phospholipid bilayer hydrophilic heads hydrophobic tails, with proteins inside of it.
Its function is for protection, separation and its proteins allow adherence/binding/communication to other cells
characteristics of the membrane include being similar in all cells and being selectively permeable
define nucleoid, where is it and what cell has it?
nucleoid is a region of the cell where the DNA is located in a prokaryotic cell
define cytoplasm and explain its importance
jelly-like substance important to every cell
functions to house and maintain an optimal environment for the cellular organelles
area where the rest of the cells contents are
what are the functions of ribosomes and compare them in prokaryotes and eukaryotes.
they synthesize proteins
eukaryotic are similar to prokaryotic ribosomes but eukaryotes are bigger
they consist of rRNA (ribosomal RNA) and more than 50 protein molecules
(about 25 nm in eukaryotes)
define the outer membrane, and where it is found.
it is an additional phospholipid membrane found outside the peptidoglycan layer technically apart of the cell wall
what is a capsule? Is it present in all prokaryotic cells or eukaryotic cells?
slimy (outermost) layer, made of polysaccharides that help protect the cell, present in some prokaryotic cells.
What is pili where are they found and what do they do?
hairlike structures projecting from the cells surface, that help bacteria to adhere to other cells
present in some prokaryotic cells
What is the cytoskeleton in prokaryotic cells?
it is a protein filaments structure
are important for cell division
movement
maintaining the cell shape
what is the endomembrane system (inside the membrane) and what is it composed of? (6 organelles)
interconnected system of membrane-enclosed compartments
1. Cell membrane
2. Nuclear envelope
3.ER
4.Golgi apparatus
5.Lysosomes
6.vesicles
what are vesicles and what do they do?
they are tiny membrane surrounded structures that shuttle substances between various components using the cytoskeleton
What is the nucleus and what is important about it?
it contains most of the DNA of the cell and is usually the largest
- Site of ribosome assembly
- Site of DNA replication
3.Site where gene transcription is turned on/off
Define nucleolus, where is it and what does it do?
it is within the nucleus and assembles the ribosomes
is about 1.5um long
what are some organelles that can be in prokaryotes? (four just prokaryotic / six both E and P)
1.cell membrane (both E and P)
2. Cytoskeleton (both E and P)
3.cytoplasm (both E and P)
4. Ribosomes (both E and P)
5. Cell wall (both E and P)
6. Flagella (both E and P)
7. outer membrane
8. Capsule
9. Pili
10. nucleoid
What is the nuclear envelope and what is its purpose?
it is a double membrane surrounding the nucleus
it uses pores to control the movement of molecules that go in and out