What is in a scientific articleplus DNA Structure and Function
Bonus #1 is due 10/02/08.
Bonus #2 is due 11/25/08.
Scientists communicate by publishing their findings in journals…
What is in a journal article?
What is in a journal article?
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Basic info: who, what, where, when
The abstract is a summary of the rationale and results.
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The introduction has background information.
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What is this?
References are how scientists cite other people’s ideas or data.
(Castrogiovanni et al., 1998)
Castrogiovanni P, Iapichino S, Pacchierotti C, Pieraccini F. 1998. Season of birth in psychiatry: a review. Neuropsychobiology 37:175–181.
(Castrogiovanni et al., 1998)
Using other’s ideas or data is fine, but not citing where the information came from is plagiarism.
Castrogiovanni P, Iapichino S, Pacchierotti C, Pieraccini F. 1998. Season of birth in psychiatry: a review. Neuropsychobiology 37:175–181.
SUBJECTS AND METHODSTo investigate the influence of birth season on
examination marks, we used the (anonymous) examination results from 1995–2001 of undergraduate students at the University of Vienna, together with their dates of birth…….
Materials and methods or other synonymous sections detail how the experiments were done.
RESULTSThe distribution of scores attained by male and
female students is associated with their birth season (see data in Table 1)………
The results section details the outcomes of the experiments.
RESULTSThe distribution of scores attained by male and
female students is associated with their birth season (see data in Table 1)………
The results section details the outcomes of the experiments, and refers to the tables and figures in the paper.
Figures are graphical representations of data.
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Sometimes tables are used.
DISCUSSIONWe find that examination scores are related to
season of birth in both female and male students, indicating that there could be some biologically significant underlying ontogenetic or early life-history mechanism………
The discussion is where the results are explained and related to other research.(sometimes it is combined with the results)
What is in a journal article?
Bonus #1 asks you to submit an article relevant to class.
How is information transferred between cells?
Fig 9.2
Different strains of bacteria are injected into mice.
How is information transferred between cells?
Fig 9.2
How is information transferred between cells?
Fig 9.2
How is information transferred between cells?
Fig 9.2
How is information transferred between cells?
What has happened to the bacteria?
Fig 9.2
• DNA is the transforming agent Fig 9.3
If these two can win a Nobel prize…
James Watson andFrancis Crick
The Structure of DNA
Rosalind Franklin Data showing uniformity of DNA structure.
Fig 9.13
Fig 9.8
Nucleotides have a sugar backbone
Fig 9.8
This subtle difference in structure has profound effects.
Fig 9.8
Plus four different bases
Together with a phosphate = nucleotide
Fig 9.9
Together with a phosphate = nucleotide
Fig 9.9
Fig 9.11
Connect nucleotides by covalent bond = strand
Fig 9.17
DNA is typically double stranded
The strands are connected by
hydrogen bonds
• Base pairing in DNA
Figure 7-10
Fig 9.17
• Two representations of the DNA double helix
Figure 7-9
Fig 9.18
Fig 12.1
DNA stores information, but does not do anything. The information must be expressed to be useful.
a gene
The relationship between DNA and genes
promoter coding region terminator non-geneDNA
DNA Composition:In humans:
•Each cell contains ~6 billion base pairs of DNA.
•This DNA is ~2 meters long and 2 nm wide.
•~97% does not directly code for amino acids
•In a single human cell only about 3-5% of genes are expressed at a time.
Width of DNA
Length of human DNAin each cell
DNA from a single human cell is ~2 meters long and 2 nm wide
DNA Composition:In humans:
•Each cell contains ~6 billion base pairs of DNA.
•This DNA is ~2 meters long and 2 nm wide.
•~3% directly codes for amino acids
•~10% is genes
•In a single human cell only about 5-10% of genes are expressed at a time.
a gene - DNA used to produce RNA or protein
The relationship between DNA and genes
promoter coding region terminator non-geneDNA
Five Perspectives of a Gene
Genes act as units of heredity…storing and passing on information.
Genes act as units of heredity…storing and passing on information.
Genes are seen as a cause of disease
Genes are seen as a cause of disease
Sickle-cell anemia is caused by a single nucleotide change in the hemoglobin gene Fig 16.1
Genes code for proteins
Fig 12.1
Proteins are the “doers” of the cell.They act as:•Enzymes•Structural Support•Transporters•Signals
Genes code for proteins…
Genes act as switches, controlling development
Genes act as switches, controlling development
Genes are replicators(selfish gene)
From “Biology 7th ed.” by Campbell et alfig 19.14
Fig 9.4
Viruses infect living cells, take over, and produce more virus.
Bodies are vessels for the transmission of genes
Five Perspectives of Genes:
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
5. Genes are replicators (selfish gene)
Transposons
Genes are replicators (selfish gene)
Transposons: mobile DNA
Section 17.3
Barbara McClintock, discoverer of transposons
One type of transposon moves from place to place without increasing the number of transposons…
Section 17.3
Fig 17.12C
Retro-transposons replicate via an RNA intermediate, thereby increasing their number.
Transposons are self-moving DNA
Fig 17.13
Transposons move within genomes via the action of transposase
Fig 17.14
Fig 17.11
transposase transposon
Fig 17.11
Fig 17.11
Fig 17.11
Fig 17.11
Genes are replicators(selfish gene)
From “Biology 7th ed.” by Campbell et alfig 19.14
Genes are replicators (selfish gene)
Transposons: mobile DNA
Fig 17.13
Five Perceptions of Genes:
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
5. Genes are replicators (selfish gene)
Protein
DNA is used to produce RNA and/or proteins, but not all genes are expressed at the same time or in the same cells.How do cells control which genes are expressed?
What is in a scientific articleplus DNA Structure and Function
Bonus #1 is due 10/02/08.
Bonus #2 is due 11/25/08.