Introduction to the Living Cell Flashcards
What is a cell?
Cells are the fundamental unit of all living thing on earth. They take nutrients and free energy from their surroundings and duplicate. All cells arise from the division of pre-existing cells.
Define Taxonomy
Discipline of defining groups of biological organisms based on shared characteristics
Define Phylogenetics
The study of evolutionary relationships between groups of organisms
What is the history of cell discovery?
•Origin of the word “cells” was by Robert Hooke (1665), after observing slices of cork under a microscope, calling the holes “cells” as they resemble the small rooms of Monks.
Antonie van Leeuwenhoek was first to see and describe single-celled microorganism, calling them “animalcules”. He observed algae growth in water using a microscope with better lens he made himself. First to observe RBCs, sperm, protozoa and bacteria
How was cell division discovered?
•Theodor Schwann (studied animals) and Matthias Jakob Schleiden (studied plants) came to the conclusion “All living things are composed of cells and cell products.”
•Hugo van Mohl discovered cell division, but Barthélémy du Mortier proceeded him as he observed mid-like partition b/w original and new cells.
Rudolf Virchow was given credit for “omnis cellula e cellula” (“cells are created through division of pre-existing cells”). Doesn’t credit Robert Remak for stating “binary fission was the means of reproduction of new animal cells”.
What are the 3 major domains of a cell?
The three major domains of cells, which evolved in the following order are:
Bacteria (Eubacteria) — Archaea (Archaebacteria) — Eukaryotes
What are the universal features of cells on earth?
•Phospholipid bilayer
•Exchanging molecules with their environment
•Heredity info stored in DNA
•DNA fragment corresponding to a single protein = a gene
•Translate RNA into protein in the same way
•Cells are made from the same basic building blocks.
•Sunlight is the ultimate source of most biological energy
•Role of ATP as the main energy currency (in metabolism)
•“Life is a pattern of flux”
Homeostasis
Explain the meaning of ‘Life is a pattern in flux’
•Cells divide and cells die. Rudolf Schoenheimer discovered molecules in our body are almost continuously being replaced, i..e they have a turnover rate (e.g. water). Some tissues have a higher turnover rate than others, for example the gastrointestinal lining (5 days), compared to red blood cells (120 days), compared to cerebral cortex (close to persons age).
98% of human body is replaced in one year.
What is the exception to the ‘Life is a patter in flux’ rule?
The exception is DNA. It is conserved (semi-conservative replication).
What is compartmentalisation?
Eukaryotic cells are compartmentalized, in other words, they have many organelles performing specific functions which have plasma membranes surrounding them. Prokaryotes do not have this.
