Lecture 2a Flashcards
Elements common to all living cells
-Plasma membrane
-Cytoplasm
-Chromosome
-Ribosomes
-Cytoskeleton
Plasma membrane
surrounds all cells, a bilayer made of phospholipid molecules with embedded protein
controls the flow of substances in and out of a cell
what are the characteristics of a lipid bilayer
hydrophobic barrier to water-soluble substances
selected cells can penetrate cell membranes through transport channels
selective transport maintains the specialized internal environments required for life
DNA
Genetic info of all cells
is hereditary
is located in the centre region (nucleus)
double helix bond formed by 2 complementary strands of nucleotides held together by hydrogen bonds
RNA
messenger of DNA, nucleic acid present in all living cells, carries instructions from DNA to be passed down across the cell
tRNA
a small RNA molecule that plays a key role in protein synthesis
ribosomes
technically not a organelle; proteins + rRNA
its the sight of protein synthesis
MAKES PROTEIN
Whats the difference of ribosomes in prokaryotic and eukaryotic cells
p= float around in cytosol
e=attatched to the nuclear envelope or too rough ER or floating in cytosol
Cytoplasm
between the plasma membrane and the central region. holds the internal components of a cell together and protects them
includes the cytoskeleton and cytosol
Cytoskeleton
Maintains cell shape and plays a key roll in cell division and chromosome seggregation
Cytosol
the aqueous portion of the cytoplasm in an intact cell, containing water, dissolved ions and various molecules
All organsims consist of one of two cell types
Prokaryotes and eukaryotes
Prokaryotes Domains
Bacteria and Archaea
Eukaryotes domains
Eukarya; Animals, plants, fungi
Prokaryotes key charcteristics
Lack a nucleus; DNA is located in a region called the nucleoid.
No membrane-bound organelles.
Common shapes: spherical, rodlike, and spiral.
Typically have a single circular DNA molecule (prokaryotic chromosome).
Prokaryotic cell structure
surrounded by a plasma membrane and often rigid cell wall
the outter layer can be a glycolax (loose slime layer or firm capsule
Contain ribosomesand may have structures like flagella for movement and pili for adhesion and mating.
Relate plasmids and prokaryotic cells
Some contain extrachromosomal DNA (plasmids), which can carry genes for antibiotic resistance and can transfer between cells.
Eukarya key charcteristics
Have a nucleus and cytoplasmic organelles enclosed within a plasma membrane.
More complex than prokaryotic cells, with a well-defined endomembrane system.
Eukaryotic cell structure
Contain various organelles for specialized functions (e.g., mitochondria for cellular respiration).
Ribosomes can be free in the cytosol or attached to membranes.
A complex cytoskeleton supports cell structure and aids in transport and division.
Key differences between eukaryotes and prokaryotes
Prokaryotes are simpler, lacking a nucleus and membrane-bound organelles, while eukaryotes are more complex, featuring compartmentalized structures and specialized functions.
