Themes in the Study of Life

Page
5

Fig. 1-10

Nucleus

DNA

Cell

Nucleotide

(a) DNA double helix

(b) Single strand of DNA

Slide 51

Genes control protein production indirectly

DNA is transcribed into RNA then translated into a protein

An organism’s genome is its entire set of genetic instructions

Slide 52

Systems Biology at the Levels of Cells and Molecules

The human genome and those of many other organisms have been sequenced using DNA-sequencing machines

Knowledge of a cell’s genes and proteins can be integrated using a systems approach

Slide 53

Fig. 1-11

Slide 54

Fig. 1-12

Outer membrane

and cell surface

Cytoplasm

Nucleus

Slide 55

Advances in systems biology at the cellular and molecular level depend on

“High-throughput” technology, which yields enormous amounts of data

Bioinformatics, which is the use of computational tools to process a large volume of data

Interdisciplinary research teams

Slide 56

Theme: Feedback mechanisms regulate biological systems

Feedback mechanisms allow biological processes to self-regulate

Negative feedback means that as more of a product accumulates, the process that creates it slows and less of the product is produced

Positive feedback means that as more of a product accumulates, the process that creates it speeds up and more of the product is produced

Animation: Negative Feedback

Animation: Positive Feedback

Slide 57

Fig. 1-13

Negative

feedback



Excess D

blocks a step

D

D

D

A

B

C

Enzyme 1

Enzyme 2

Enzyme 3

D

(a) Negative feedback

W

Enzyme 4

X

Positive

feedback

Enzyme 5

Y

+

Enzyme 6

Excess Z

stimulates a

step

Z

Z

Z

Z

(b) Positive feedback

Slide 58

Fig. 1-13a

Excess D

blocks a step

(a) Negative feedback

Negative

feedback

D

D

D

D

C

B

A

Enzyme 1

Enzyme 2

Enzyme 3

–

Slide 59

Fig. 1-13b

Excess Z

stimulates a step

(b) Positive feedback

Z

Positive

feedback

Enzyme 4

Enzyme 5