W1- Lecture 1- prokaryotic and eukaryotic cells Flashcards
Why is a plasma membrane import for cells ?(6)
Encloses all cells;
Separates from environment;
Lipid bilayer;
Selective channels - proteins that control import and export of substances;
Ability to deform without tearing;
Can grow with cell without losing continuity.
Label a phospholipid
Hydrophilic head
Hydrophobic tail
What is the major use of rna
translate information in DNA into protein
Where does protein synthesis take place ?
Right
8 major characteristics of all cells
Plasma membrane Dna Genetic code same in all cells(some exceptions ) Rna Proteins determaiun structure and functions of cell Ribosomes All cells need energy All cells are derived from other cells
Why do cells need energy
Maintains internal environment
Synthesise essential compouds
Tranfer energy from one site to another
Why do we think all life derived from prokaryotic cells ?
Similarities among living cells is too great
Common cell components (amino acids, sugars, nucleotides & fatty acids) which can be made in vitro from simple organic molecules (carbon, nitrogen, oxygen);
Evidence from fossils
Prokaryote 3.5 billion years ago
Last eukaryotic ancestor 1.5 billion years
What size are prokaryotes
Small less then 10μm
What shapes are prokaryotes ?
Spherical
Rod
Spiral
What compound can we find in prokaryotic cell walls ?
peptidoglycan
What acid makes up gram postive bacteria ?
Lipoteichoic acid
What does a gram negative bacteria have that isn’t shared with gram postive bacteria ?
Porins
Endotoxins/LPS(outer membrane )
Periplasmic space
Which structures do both gram postive and negative prokaryotes share ?
Flagella Pilus Capsule Cell wall Peptiglycan Cytoplasmic membrane
By what process do prokaryotes replicate+ explain this
Binary fission
Name three food sources for prokaryotes
Sugars Amino acids Fats C form co2 N from N2
What is the process of conjugation
Bacterial cells can exchange gene information between different species;
(horizontal gene Tranfer )
Explain the process of conjugation
Donor cell attaches to recipient cell through a pilus (F-pili) and transfers DNA;
Mention of DNA polymerase
Relaxasome transferasome
Why is conjugation important for prokaryotes
Enhances natural selection advantage.
Why is horizontal gene transfer a problem ?
Increases antibiotic resistance, does need mutations can just transfer antibiotic resistance to other bacterial
Name 4 things all bacteria have
Plasma membrane
Cytoplasm
70s ribosomes
Nuclear region containing DNA
Some bacteria may also have ___
Pilus Capsule cell wall Inclusions (to store nutrients ) Plasmid Flagella Fimbriae(attachment pilus )
Label a bacteria / prokaryotic cell
.
What surrounds a nucleus
Most are enclosed in a double membrane
Where is the site of translating DNA into proteins (in eukaryotes )?
Ribosomes
