Lecture 13: Introduction To Molecular And Cellular Biology Flashcards
Who discovered the cell?
Robert Hooke
The first two tenets of the cell theory was created by which two scientists?
Matthias Jakob Schleiden and Theodor Schwann
What are the 3 points of cell theory?
- All living organisms are composed of one or more cells
- The cell is the most basic unit of life
- All cells arise only from pre-existing cells - Rudolph Virchow added this tenet in 1855
When did Schleiden and Schwann develop the first two points of the cell theory?
1839
What are the basic properties of cells? (9)
- Complex and organized
- Activity controlled by genetic blueprint
- Can reproduce - make copies of themselves
- Assimilate and utilize energy
- Carry out many chemical reactions (enzymes)
- Engage in mechanical activities
- Respond to stimuli
- Self-regulate - determine whether they need to perform a certain activity
- Evolve
What does it take to make a cell? (3)
- Information
- Chemistry
- Compartments
All cells possess…
DNA
What does DNA provide for the cell
Information necessary to build proteins - which is the cells primary machinery
What is DNA the hereditary material of?
Genes and RNA
What is the order of the cell replication rate for higher eukaryotic cells, bacteria and fungi?
Bacteria < Fungi < Higher eukaryotic cells
DNA is transcribed to _____ which is then translated to _____
RNA
Proteins
During cell division, the DNA is…
Replicated
Differentiation is?
A cell that changes into the starting cell of other types of cells, one cell that can evolve into another type of cell. The genetic information stored in the DNA of the cell determines if the cell can differentiate, and which type of cell it can differentiate into
E.g. stem cells, which can be a variety of cells such as immune cell, sex cell, muscle cell, fat cell, bone cell, blood cell, nervous cell, epithelial cell
Which cell type lacks the cell nucleus and therefore has no DNA?
Red blood cells, they eject their nucleus, through nuclear ion
Mature blood cells have no organelles and cannot synthesize RNA
Cannot divide and have limited repair capabilities
This evolution has occurred to accommodate hemoglobin carrying capacity
Example of building blocks of the cell…? (3)
Amino acids - make up proteins
Nuclei Acids - carry genetic information
Lipids - help us to make cellular components
Chemical origin of life?
Abiogenesis
The primordial soup hypothesis was created by which two scientists?
Ovarian and Haldane
What is the primordial soup hypothesis?
Primitive earth has a variety of simple organic compounds that chemically reacted with energy to synthesize more complex organic compounds from simpler inorganic precursors
Molecules: Nitrogen, Ammonia, Methane, Carbon dioxide, Water, Hydrogen gas
Miller-Urey experiment: Pre-biotic chemistry is…
Chemical experiment that stimulated the conditions thought to exist on the early earth and to test the chemical origin of life under those conditions
Compartments of a cell are defined by what factor?
Single or double lipid layer membrane
E.g. of compartments - Mitochondria, chloroplasts, vesicles, ER, nucleus
What are the functions of compartments?
They establish physical boundaries that enable cell to carry out different metabolic activities
Generate micro-environment to spatially and temporally regulate biological processes
Two main types of cells are…?
Prokaryotic - Bacteria and Archaea
Eukaryotic - Protists, fungi, plants animals, eukaryotes come from archaea, not from bacteria - archaea and bacteria are unicellular
Eukaryotic cell vs Prokaryotic cells…
Eukaryotic cells have a defined nucleus
Prokaryotic cells have no defined nucleus
Prokaryotic cells are organized into two groups which are…
Archaea and Bacteria
Prokaryotes came before eukaryotes
Archaea are found…
In extreme environments
Bacteria are found in…
Ubiquitous habitats (everywhere)
Features of archaea
Have a membrane lipid with branched hydrocarbons
Chromosomes are circular
Lack a nuclear envelope
Lack membrane bound organelles
Methionine is the initiator amino acid for protein synthesis
Lack peptidoglycan in the cell wall
Growth not inhibited by streptomycin and chloramphenicol
Histones are associated with DNA
Contains several types of RNA polymerase
Features of Bacteria
Chromosomes are circular
Lack a nuclear envelope
Lack membrane bound organelles
Features of Eukarya
Methionine is the initiator amino acid for protein synthesis
Lack peptidoglycan in the cell wall
Growth not inhibited by streptomycin and chloramphenicol
Histones are associated with DNA
Contains several types of RNA polymerase
Typical features of a prokaryotic cell
- Single cell organism
- Size: 1-10 microm
- Ribosomes are present but smaller
- Reproduce sexually and asexually
- No nucleus or organelles
- Genetic material found in nucleotide (nucleus-like)
- DNA arranged in circular chromosomes and often circular plasmids (extrachromosomal DNA)
Typical features of a Eukaryotic cell
- Typically multicellular organisms, but can be unicellular as well (Protozoa, yeasts)
- Size: 10-100 microm
- Nucleus contains genetic material arranged in linear chromosomes
- Membrane-bound organelles
- Ribosomes are larger
Animal vs. Plant cells
Animal:
- Lysosomes - used to degrade macromolecules
- Microvilli
Plant:
- Vacuole - like lysosome but more functions - storage - structural support
- Cell wall
- Chloroplast
- Plasmodesmata
