Lecture 1 (chapter 1.2, 1.3) Flashcards
What are the tenets of the cell theory?
- All organisms are composed of one or more cells
- The cell is the structural unit of life
- Cells can arise only by division from a preexisting cell
Why do cells internally program themselves to die?
Cells are no longer needed or pose a risk of becoming cancerous
What sort of movement are atoms in a constant state of?
random (stochastic) propelled by thermal energy they acquire from their environment
What is a protein?
polypeptide chains consisting of hundreds of amino acid building blocks that fold into a precise three-dimensional structure
Where is genetic information stored?
DNA which is packaged into a set of chromosomes that occupy the space of a cell nucleus
What do genes do?
Genes facilitate the construction of cellular structures, the directions for running cellular activities and the program to duplicate themselves
What division is it when the mother cell unequally divides leaving one of the cells retaining nearly all of the cytoplasm despite receiving half the genetic material?
When a human oocyte divides
What division is it when the mother cell unequally divides leaving one of the cells retaining nearly all of the cytoplasm despite receiving half the genetic material?
When a human oocyte divides
What is an enzyme?
Molecules that greatly increase the rate at which a chemical reaction occurs
Define metabolism
The sum total of the chemical reactions in a cell
Features held in common by prokaryotic and eukaryotic cells
- Genetic information encoded in DNA
- Both have DNA-containing chromosomes
- Similar mechanisms for transcription and translation (including similar ribosomes)
- Similar apparatus for conservation of chemical energy as ATP
- Similar mechanism for synthesising and inserting membrane proteins
- Plasma membranes and Proteasomes (protein digesting structures) of similar construction
Features of eukaryotic cells not found in prokaryotes
- Division of cells into nucleus and cytoplasm, separated by a nuclear envelope containing complex pore structures
- Complex chromosomes and associated proteins capable of compacting into mitotic structures
- Complex membranous cytoplasmic organelles (e.g endoplasmic reticulum, Golgi complex, lysosomes)
- Specialised cytoplasmic organelles for aerobic respiration (mitochondria/chloroplasts)
- Complex cytoskeletal system (e.g actin filaments) and complex flagella and cilia
- Ability to ingest material by enclosure within plasma membrane vesicles (phagocytosis)
- Cell division using a microtubule-containing mitotic spindle that separates chromosomes
- Presence of two copies of genes per cell (diploidy), one from each parent
- Presence of three different RNA synthesising enzymes (RNA polymerases)
- Sexual reproduction requiring meiosis and fertilisation
What is a nucleoid?
A poorly demarcated region of the cell that lacks a boundary membrane to separate it from the surrounding cytoplasm
What is a nucleus?
A region bounded by a complex membranous structure called the nuclear envelope
What is a chromatin?
A complex nucleoprotein that is formed when chromosomal DNA of eukaryotes is tightly associated with proteins
What is mitochondria?
Where chemical energy is made available to fuel cellular activities
What is an endoplasmic reticulum?
Where many of a cell’s proteins and lipids are manufactured
What is a Golgi complex?
Where materials are sorted, modified and transported to specific cellular destinations
How does material move within a prokaryotic cell?
Simple Diffusion
What is the definition of Biofilms?
Complex, multispecies communities (typically associated with prokaryotic cells)
How does material move within a eukaryotic cell?
Cytoplasmic membranes of eukaryotic cells form a system of interconnecting channels and vesicles that function in the transport of substances from one part of a cell to another, as well as between the inside of the cell and its environment
When was the first culture of human cells begun and from what was it obtained from?
1951, the cells were obtained from a malignant tumour and named “HeLa” cells after the donor
What is the hierarchical organisation of living systems?
Cellular level
Organismal level
Populational level
Ecosystem level
What are the two streams of chemical reactions that occur in cells?
Catabolic pathways and Anabolic pathways
What is the purpose of cell receptors?
A cell’s receptors provide pathways through which external stimuli can evoke specific responses in target cells
What are some ways cells respond to specific stimuli?
- alter their metabolic activity
- moving from one place to another
- committing suicide
What do cells possess receptors for?
- Hormones
- Growth factors
- Extracellular materials
- Substances on the surfaces of other cells
What did the 1891 experiment conducted by Hans Driesch, a German Embryologist, entail?
He found that he could completely separate the first two or four cells of a sea urchin embryo and each of the isolated cells would proceed to develop into a normal embryo
How is the proportion of oxygen different in lipids and carbohydrates?
The proportion of oxygen in lipids is less than in carbohydrates
What is molecular biology?
The study of the chemical structures and processes of biological phenomena that involve the basic units of life
What are organic compounds and what are the different types?
Organic compounds are carbon based. They are linear, cyclic and aromatic.
What do the attached functional groups determine?
- Physical properties
- Reactivity
- Solubility in aqueous solutions of organic and all chemical compounds
How do fats act as chemical energy stores?
Fats are rich in chemical energy and a gram of fat contains over twice the energy content of a gram of carbohydrates
Carbohydrates function as short term energy stores and fat acts as a long term energy supply
What are adipocytes?
Cells specialised for fat storage, breakdown and synthesis.
Fats are insoluble in water and stored in adipocytes which contain one large or multiple smaller lipid globules
