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.