091709-BCH311 - HW Chapter 2 = up to#24 Biochemical Buffers...

Info icon This preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Biochemical Buffers A buffer is something that resists change - in terms of acid and base chemistry, a buffer solution tends to resist change in pH when small or moderate amounts of a strong acid or strong base are added A buffer solution consists of a mixture of a weak acid (HA) and its conjugate base (A - ), a commonly used example of a buffer is a mixture of monohydrogen phosphate (HPO 4 2- ) and dihydrogen phosphate (H 2 PO 4 - ) Many biological reactions will not take place unless the pH remains within fairly narrow limits Analysis of the titration curve of a buffer can yield important insight into when a particular buffer might be chosen for a particular reaction A buffer solution can maintain the pH at a relatively constant value because of the presence of appreciable amounts of both the acid and its conjugate base The two major buffering systems in living organisms are H 2 PO 4 - /HPO 4 2- (cells) and H 2 CO 3 /HCO 3 - (blood) Fig. 2-13b, p. 51
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Fig. 2-15, p. 57 Biochemical Buffers The H 2 PO 4 - /HPO 4 2- pair is a suitable buffer at a pH near 7.2 The plateau region in a titration curve, where the pH does not change rapidly, covers a pH range extending approximately one pH unit on either side of the p K a
Image of page 2
Table 2-8, p. 60
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Summary 2-5, p. 61
Image of page 4
Fig. 1-1, p. 2
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
The Three Domains of Life All living organisms fall into one of three large groups ( or domains ) that define three branches of evolution from a common progenitor Two large groups of single-celled microorganisms can be distinguished on genetic and biochemical grounds: Bacteria and Archaea Bacteria inhabit soils, surface waters and the tissues of other living or decaying organisms The Archaea, recognized as a distinct domain by Carl Woese in the 1980s, inhabit extreme environments, such as salt lakes, hot springs, highly acidic bogs, and the ocean depths Archaea and Bacteria diverged early in evolution All eukaryotic organisms, which make up the third domain, Eukarya, evolved from the same branch that gave rise to the Archaea: eukaryotes are therefore more closely related to archaea than to bacteria
Image of page 6
The Three Domains of Life Phylogeny of the three domains of life - the basis for family trees is often similarity in nucleotide sequence of the ribosomal RNAs; the more similar the sequence, the closer the location of the branches
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
The Three Domains of Life Within the domains of Archaea and Bacteria are subgroups distinguished by their habitats In aerobic habitats where oxygen is abundant, organisms derive energy from the transfer of electrons from fuel molecules to oxygen In anaerobic habitats, virtually devoid of oxygen, organisms obtain energy by transferring electrons to nitrate (forming N 2 ), sulfate (forming H 2 S), or CO 2 (forming CH 4 ) Obligate anaerobes die when exposed to oxygen, while facultative anaerobes can live with or without oxygen Organisms can also be classified according to how they obtain the energy and carbon they need for synthesizing cellular material For example, phototrophs trap and use sunlight, and chemotrophs derive their energy from the oxidation of a chemical fuel
Image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern