- prion- infectious protein
Aristotle thought that plants gain mass by taking it from the soil but that was disproven by Helmont who did an experiment where he grew a plants over 5 years and
only added water. The soil weighed the same while the plant mass grew- he disproved the hypothesis
- Strong inference: 1.Devise multiple hypotheses.
Design experiment(s) to eliminate one or more of the hypotheses.
Carry out the experiments in a manner that gives a clean result (reliable).
- Experiment to figure out how info is transferred from cells- Living S cells injected > mouse dies, living R cells> mouse lives, killed S cells> mouse lives,
cells and living R cells> mouse dies and living S cells found in blood. DNA destroyed in S cells causes the mouse to live bc it kills the S cell
- Nucleotides- sugar backbone. 2’ OH- ribose. 2’ H- deoxyribose. Purines- Adenine, Guanine. Pyrimidines- cytosine, thymine (DNA), uracil (RNA)
- A strand is formed by covalently bonded nucleotides and 2 strands are connected by hydrogen bonds= DNA. Purine pairs with a Pyrimidine
- DNA stores information, but does not do anything.
The information must be expressed to be useful.
- A gene in DNA is composed of: promoter, coding region, terminator, non-gene DNA
- 5 Perspectives of a gene: 1)
Genes act as units of heredity 2)Genes are seen as a cause of disease 3)Genes code for proteins 4)Genes act as switches, controlling development
(Ex . babies) 5) Genes are replicators (selfish gene)
- Sickle-cell anemia is caused by a single nucleotide change in the hemoglobin gene
. (Glu becomes Val) (cause of disease)
- Proteins act as enzymes, structural support, transporters, signals
- Viruses infect living cells, take over, and produce more virus.
transposon- A segment of DNA that is capable of independently replicating itself and inserting the copy into a new position within the same or another chromosome
or plasmid. Transposons act somewhat similarly to viruses and in humans are an underlying cause of hemophilia, certain cancers, and other diseases. In other
organisms, they can become a permanent and even beneficial part of the genome, as in maize corn, where transposons account for half the genome, and certain bacteria,
where genes for antibiotic resistance can spread by means of transposons. Transposase makes a staggered cut at the target site producing sticky ends, cuts out the
transposon and ligates it into the target site. A DNA polymerase fills in the resulting gaps from the sticky ends and DNA ligase closes the sugar-phosphate backbone.
This results in target site duplication and the insertion sites of DNA transposons may be identified by short direct repeats (a staggered cut in the target DNA filled by
DNA polymerase) followed by inverted repeats (which are important for the transposon excision by transposase). (kerns mosaics= transposition during development)
- Living organisms must fill all of these: 1) They must have organization. 2) They must have metabolism 3) they must respond to the environment 4) they must be able