W2 Prokaryotes and Eukaryotes Flashcards
Examples of unicellular organisms:
All bacteria, protozoa, unicellular algae, unicellular fungi
Give examples of Multicellular organism
Pluricellular fungi, algae, parasites, plants, animals
Features of a RBC (5)
Transport oxygen.
Biconcave shape
No nucleus
Contain haemoglobin
Small and flexible
What are the functions of Nerve cells? (neurons)
What is their structure?
Transmit electrical impulses to other nerve cells, muscle or gland cells in response to the environment stimuli
Thin and long cells
How is the human body organised into levels of increasing complexity?
Cell, tissue, Organ, Organ System
Light microscope function
To observe living cells in a tissue and some internal structures
Fluorescence microscope function
Fluorescence signals can be detected through excitation of fluorophores.
Function- To visualise and monitor the localisation of labelled molecules within a cell or tissue.
What is an Electron microscope? (EM)
Technique for obtaining high resolution images, using a beam of electrons (very short wavelengths) as the source of illuminating radiation.
What are the two types of electron microscopes?
TEM- Transmission electron microscope
SEM- Scanning electron microscope
What is the practical resolution limit of a modern EM?
Around 2nm
What are the 4 major organic macromolecules?
Carbohydrates/Polysaccharides
Proteins
Lipids
Nucleic acids
What are macromolecules?
Polymers made by specific
repeating molecular units, monomers
What are monomers?
▪ building blocks or subunits
▪ smallest units of molecules that can join with each other to form larger molecules, polymers
What is anabolism?
Building up
Cells link monomers together to form a polymer
through polymerisation or condensation reactions
What is catabolism?
Breaking down
polymers are broken down into
smaller molecules by hydrolysis
What is Anabolism?
Catabolism and Anabolism reactions
What are the polymers made from fatty acids and their function?
- Lipids
- Energy storage/ Biomembranes/hormones
What are the polymers made from amino acids and their function?
- Proteins/Peptides
- Structure/ Enzymes/ Multiple functions
What are the polymers made from sugars and their function?
- Oligo/Polysaccharides
- Energy source
What are the polymers made from nucleotides and their function?
- Nucleic acids (DNA/RNA)
- Store/encode genetic information/ energy transfer
What are the 2 types of distinct cell?
Prokaryotes and Eukaryotes
What are the 3 ways that prokaryotes and eukaryotes differ?
Prokaryotes
- WITHOUT nucleus
- ONLY ONE compartment
- Simple internal organisation
Eukaryotes
- WITH nucleus
- Internal membranes that enclose the organelles - Complex organisation
Prokaryotes:
Monocellular or multicellular?
Smaller or bigger than eukaryotes?
What are the 2 cellular domains?
Mostly monocellular
Smaller and simpler than eukaryotic cells
Bacteria and Archaea
- Structurally similar but different biochemical abilities
Where do archaea bacteria live?
In normal habitats but most of them grow at extreme environmental conditions (pH, temp, salt conc)
Overview of prokaryotic cell structure:
- Membrane-enclosed nucleus is absent
- Lack of membranous organelles
- Simple internal structure
External Glycocalyx/capsule and different appendages
*Tough protective coat (cell wall), around the plasma membrane
*Single internal compartment containing the cytoplasm and the genome
What are the prokaryotic cell surface layers?
Plasma membrane
Cell wall
Glycocalyx
What is the plasma membrane?
A flexible lipid bilayer membrane, made up phospholipids and proteins. Do not contains sterols.
What is the cell wall?
A rigid structure composed of peptidoglycan. Different in Gram +/-
Maintenance of cell shape and structural integrity
What is a Glycocalyx?
What does it protect the cell against?
Gelatinous coating composed of polysaccharides or polypeptides
If organised (capsule)
If loosely organised and attached (slimy layer)
➢ It protects the cell against dehydration, immune system (phagocytosis) and antibiotics.
➢ It also an adherence factor.
Intracellular composition of a prokaryote:
- Cytoplasm- a gel-like internal fluid
- Singular circular genomic DNA in the nucleioid
- Not associated with histone proteins
- No nucleus
Name some prokaryotic cell appendages:
FLAGELLUM: (pl flagella) which are whip-like structure
Locomotion- Act as a sensory structure
Fimbriae/pili- Short, fine, hair-like (up to 1,000)
- Help the cell to stick/attach to a surface
- Twitching motility
SEX PILUS- Rigid hair-like tubular structures, larger than fimbriae
- Allow the attachment to other cells (females) to transfer plasmids/DNA
Overview of eukaryotic cells?
- In unicellular (e.g. protozoa and yeasts) and
in multicellular organisms (e.g. animals) - Bigger and more elaborate than Prokaryotes
- Except for plant and fungal cells, the cell wall
is NOT PRESENT in animal/human cells! - All eukaryotic cells have a nucleus
- Many membrane-enclosed organelles
What is the cytoplasm?
All of the material inside the cell BUT outside of the nucleus
It includes cytosol and the various organelles
Highly organised and dynamic
What is cytosol?
- The part of the cytoplasm that is not contained within organelles
- The dense and viscous gel-like fluid to support and protect organelles
