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Biology Unit 2

The Chemistry of Life. Biology Unit 2. Matter. Something that has mass and takes up space. Mass. The amount of matter something contains. This differs greatly from weight!. Elements. Substances that can not be broken down into simpler forms of matter

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Biology Unit 2

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  1. The Chemistry of Life Biology Unit 2

  2. Matter • Something that has mass and takes up space

  3. Mass • The amount of matter something contains. • This differs greatly from weight!

  4. Elements • Substances that can not be broken down into simpler forms of matter • Examples include gold, oxygen, iron, calcium and lead

  5. Elements Important for Life • The most important elements for life are carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and phosphorus (P) • Calcium (Ca), Magnesium (Mg), potassium (K), sodium (Na), chlorine (Cl) and iron (Fe) are all needed in lesser amounts

  6. Atoms • The simplest particle of an element that still retains the properties of that element

  7. Parts of an Atom • The nucleus makes up most of the mass of an atom; it is made of two parts • Protons – the part of a nucleus that has a positive charge • Neutrons – the part of a nucleus that has no charge

  8. Parts of an Atom Cont'd • Electrons – negatively charged parts of an atom that orbit at high speeds around the nucleus • Overall, the charge on a normal atom is zero (neutral).

  9. Model of an Atom

  10. Molecule • Two or more atoms chemically bonded together. • Which of the examples to the left is a molecule?

  11. Compound • Made of atoms of two or more elements. • Which of the examples to the left is a compound?

  12. Water • Water is one of the most important compounds to most forms of life, due to its unique chemical properties.

  13. Adhesion • Water's ability to stick to other things

  14. Cohesion • Water's ability to stick to itself

  15. + H H O _ Hydrogen Bonding • The oxygen in water is larger and attracts that electrons shared by the hydrogen unequally. • This causes the oxygen portion to take on a slight negative charge and the hydrogen portion a slight positive one

  16. Water has a low freezing point Water has a high heat capacity (it changes temperature slowly) Help us remain warm blooded Other Properties of Water

  17. Organic Compounds • Usually contain carbon • Usually associated with living creatures • Most are polymers (large molecules made of repeating units) • These polymers are made of small molecules called monomers

  18. Dehydration Synthesis • Monomers bond together with the removal of water.

  19. Hydrolysis • Monomers are removed with the addition of water.

  20. Carbohydrates • Made of C, H and O • Monomers are called monosaccharides • Examples are sugars, starch and glycogen • Disaccharide – two monosaccharides bonded together • Polysaccharide – many monosaccharides bonded together

  21. Lipids • Made of C, H and O • Monomers are called fatty acids • Examples are fats, oils, waxes, cholesterol, steroids and some hormones

  22. Nucleic Acids • Made of C, H, O, N and P • Monomers are called nucleotides • Example are deoxyribonucleic acid and ribonucleic acid (DNA and RNA)

  23. Proteins • Made of C, H, O and N • Monomers are called amino acids • Enzymes are examples • Polypeptide – many amino acids bonded together

  24. Enzymes • Enzymes catalyze chemical reactions • This means the reactions happen faster and need less energy to take place • Complex life forms could not live without them • They are not consumed

  25. Enzyme Functioning • Enzymes work best at a particular pH, which varies with each enzyme • When temperatures increase, the rate of enzyme activity increases, until 40 degrees C is reached, then the enzyme denatures

  26. Enzyme Functioning Continued • Rates of enzyme activity increase as the concentration of substrate increases, until all of the enzymes are active, then increased substrate can not increase reaction rates.

  27. Solutions • A mixture of substances that look like one substance and are difficult to separate.

  28. Solvent • The part of the solution that is present in the largest amount • It dissolves things

  29. Solutes • Substances present in lesser amounts • Can be more than one. • The substances that get dissolved

  30. Mixtures • Two or more substances together that do not look like one substance and can usually be easily separated.

  31. Suspension • A mixture in which one or more substances settle over time. • Ex: Italian dressing

  32. Colloid • A mixture in which one substance is found in another, but it doesn’t settle. • Ex: a Jell-o fruit cup

  33. Importance of Carbon • The number of outer level or valence electrons determines how an element will react with other elements. • Most elements need to have eight valence electrons in their valence shell to be stable.

  34. In order to fill its outer electron shell, carbon forms four bonds with other elements The ability to form four bonds is what allows carbon to make polymers That’s why earth’s life forms are based upon carbon (organic) Importance of Carbon Cont’d

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