week 1 Flashcards
what does the cell theory state?
- the cell is the basic organizational unit of life
- all organisms are comprised of one or more cells
- cells come from prexisting cells
What are the two types of cells?
Prokaryotic and eukaryotic
What are the differences between a prokaryotic and eukaryotic cell?
- Prokaryotic cells have no nucleus
- Prokaryotic cells also have no membrane bound organelles or compartments
- Prokaryotes are also single-celled organisms, but can live in clusters
What is the difference between bacteria and archaea?
Bacteria live everywhere, whilst archaea are found in abnormal places such as volcanic vents and cow stomachs
What is the nucleoid?
This is an area found in prokaryotes – it consists of strings of free DNA complexed with proteins
Why do plant cells have greater sized vacuoles?
It compensates for the lack of a skeletal structure
What does the endosymbiont theory explain
The origin of the eukaryotic cell, and how it is believed that they once emerged from prokaryotic
How did things come about from the early anaerobic eukaryotic cell
There was an early anaerobic eukaryotic cell, and an aerobic bacterium that was assumed to be ancestral. Because the bacteria lives inside the anaerobic cell, it is able to survive.
Explain the engulfing of mitochondria
Mitochondria was believed to have been evolved from aerobic bacteria that was once enguled by an early anaerobic eukaryotic cell, and thus lived in symbiosis with it
Why do mitochondria have double membranes?
It was believed that mitochondria (once existing aerobic bacteria) was engulfed by an ancestral anaerobic eukaryote. It lost its membrane by being engulfed by the eukaryote, and thus the outer membrane is believed to be derived from the host when the bacterium was engulfed
How did chloroplasts evolve?
Similarly, there was an early aerobic eukaryotic cell, and a photosynthetic anaerobic bacterium.
What features of the mitochondria and the chloroplast suggest the endosymbiotic theory?
- They both have 70s ribosomes, that similar to the prokaryotic ribosomes
- Their ribosomes are also sensitive to the same antibiotics of prokaryotic ribosomes
- They have their own DNA and genome, and have kept the double membrane
- They have also kept some of their own protein and DNA synthesis components
What does the fossil record suggest?
That prokaryotes came first, and eukaryotes second
What are the four strong lines of evidence that suggest the endosymbiotic theory?
- Similarity between ribosomes
- Ribosomal sensitivity to antibiotics
- The fossil record
- Double membrane composition
What is information flow?
The flow of information within the central dogma
What are the 3 types of RNA
- Messenger RNA
- Transfer RNA
- Ribosomal RNA
What is the function of mRNA?
It is translated into protein
What is the function of tRNA?
It is used in transporting amino acids and protein synthesis
What is the function of ribosomal RNA?
It is a part of the ribosome, and has a function on structural and cataclyticism
What is the genome?
This is the communication within the cell – all that concerns the genes
What is the transcriptome
When DNA is transcribed, it forms the transcriptome.
It is all the RNA at a given point of time (it is dynamic)
What is the proteome?
This is all of the proteins at one point in time – like a photograph of all the proteins in a cell at a given time
Is the proteome a mirror of the transcriptome/genome
No, because not everything that is transcribed is translated