Chapter 1: Introduction Flashcards
Discovery of Cells Basic Properties of Cells Two Fundamentally Different Classes of Cells Viruses
How did the study of cell and molecular biology come about?
Attributed to human curiosity and human creative intelligence
Microscope
instrument that provides a magnified image of a tiny specimen
Robert Hooke
Credited with the discovery of cells - observed cork and examined empty cell walls of dead plant tissue - had a position as a curator of the Royal Society of London
Anton van Leeuwenhoek
First to describe bacteria - constructed a simple microscope of remarkable quality - observed “animalcules” in pond water
What is the smallest living organism and its approximate size?
Mycoplasma sp.
0.2 micrometer diameter
Enumerate 4 inventions/techniques created that helped enable the study of cell and molecular biology and what it accomplishes
Polymerase Chain Reaction (PCR): amplifies DNA fragments
Spectrophotometer: quantify DNA or protein extracted from a cell
Electrophoresis: separation of nucleic acids or proteins based on molecular weight
Flow Cytometer: count number of cells/chromosomes
How big is the genome of prokaryotes?
Fewer than 500 genes
Enumerate the types of microscopes
Compound Light Microscope: for viewing objects with higher magnification, not as detailed
Scanning Electron Microscope: for visualization of external structures in detail
Transmission Electron Microscope: for visualization of internal structures in detail
Matthias Schleiden
Observed that plants are made of cells
Concluded that the plant embryo arose from a single cell
Theodor Schwann
Published a comprehensive report on the cellular basis of animals
Proposed 2 tenets of the cell theory:
1) All organisms are composed of one or more cells
2) Cells are the basic structural unit of life
Rudolf Virchow
Cells can only arise from pre-existing cells
What was the first culture of human cells grown and who grew it?
HeLa cells: obtained from a malignant tumor
Researchers: George and Martha Gey
Donor: Henrietta Lacks
TRUE OR FALSE
in vitro: within the body:: in vivo: outside the body
FALSE
in vitro refers to cells that are grown outside the body in an artificial medium
in vivo refers to cells within the body
What are the basic properties of cells?
- Highly complex and organized
- Possess a genetic program and the means to use it
- Capable of producing more of themselves
- Acquire and utilize energy
- Carry out a variety of chemical reactions
- Ability to respond to stimuli
- Capable of self-regulation
- Evolve
What does it mean to be highly complex and organized?
[COPC]
Complex: greater number of cellular structures
Organized: cellular structures all have proper places within the cell
Highly precise & more regulation: less tolerance of errors in interaction of parts
Consistent: organelles have the same shape, same location, and same composition of macromolecules arranged in a predictable pattern across different cells
What is the advantage of evolution proceeding slowly at the level of cells?
Information obtained from cells in one type of organism usually has a direct application to another organism
Give an example demonstrating the complexity and organized nature of cells
Epithelial cells: line the intestine and facilitate absorption of nutrients
- have microvili that contain internals skeletons made up of filaments
- filaments are made up of actin
- have mitochondria at the basal end: provides energy to fuel transport processes
Where is the genetic information of cells stored and what are the means by which it is used?
Found in the chromosomes.
Enables the construction of cellular structures
Directs cellular activities
Guides reproduction of a cell
Mutations provide the basis for biological evolution.
How do cells reproduce?
Division wherein each daughter cells receives a complete set of genetic information from the parent cell
Differentiate between how plant cells (photosynthetic) acquire energy and how animal cells do
Photosynthetic cells capture light energy and through photosynthesis, convert this to chemical energy
Animal cells have energy pre-packaged in glucose
How do human cells acquire and utilize energy?
Glucose is released into the bloodstream via the liver where it circulates throughout the body delivering chemical energy to all the cells where it is broken down into a readily available form or energy: ATP
These are the molecules that enable chemical reactions to proceed faster
Enzymes
The sum total of all the chemical reactions in a cell
Metabolism
Enumerate the mechanical activities cells engage in
- Transport of cellular materials
- Assembly and disassembly of cellular structures
- The entire cell moves
How do the mechanical activities that occur in the cell proceed?
Changes in the shape of motor proteins and other molecules
_____ provide pathways through which external stimuli can evoke specific responses within target cells
Receptors
Enumerate the ways in which a cell responds to external stimuli
- Alteration of metabolic activities
- Moving
- Committing suicide (Apoptosis)
What is the importance of cell turnover?
Maintains the integrity of organelles and macromolecules
Ligands
Signal molecules received by the cells receptors that illicit a response
TRUE or FALSE
The robustness of a cell means it is able to protect itself from dangerous fluctuations in composition and behavior
True
What is the importance of self-regulation in a cell? Provide an example
In the event that a mistake is made during DNA replication, if the feedback circuits do not correct the mistake this could lead to a debilitating mutation such as the breakdown of the growth-control safeguards that would then lead the cell to become a cancer cell.
What is self-regulation in a cell?
The spontaneous occurrence of each step of a process within cell that serves as a trigger for the next step
LUCA
Last Common Universal Ancestor from which all cells arose from
What is evolution?
Evolution is the on-going process wherein the properties of cells continue to be modified as external and internal factors change
Enumerate the common features between prokaryotic and eukaryotic cells?
- Plasma membrane of similar construction
- Genetic information encoded in DNA using an identical genetic code, located in the nuclear region
- Similar mechanisms for transcription and translation and similar ribosomes
- Shared metabolic pathways
- Similar apparatus for conservation of chemical energy in the form of ATP
- Similar mechanism of photosynthesis
- Similar mechanisms for synthesizing and inserting membrane proteins
- Proteasomes of similar construction
Explain how eukaryotic and prokaryotic organisms, being two fundamentally different classes, can have shared properties?
The shared properties between the two indicate that eukaryotes evolved from prokaryotes which lines up with the idea that all cells arose from a single cell (LUCA)