1. Four Classes of Biological Molecules
Carbohydrates
Sugars and their polymers
Nucleic acids and nucleotides
DNA, RNA, ATP
Lipids
Various hydrophobic molecules
Proteins and amino acids

2. Carbohydrates: CH2O Monosaccharides: glucose, fructose, many others
Disaccharides: sucrose, lactose
Polysaccharides: starch, cellulose, glycogen, agar, chitin, xanthan gum

3. A nucleotide: a monomer of DNA

4. Nucleic acids are the polymers made from nucleotides.
DNA tRNA

5. Lipids Hydrophobic Contain mostly C and H, and only some O.
Fats, oils and waxes
Contain more chemical energy per gram
Why do we eat fatty foods? Survival mechanism; we evolved that way.
Insulation
Protection; cushions internal organs

6. Lipid Building blocks: Fatty Acids

8. Saturated fats – contain as many H’s as possible (saturated).
Unsaturated fats contain one or more double bonds.
Monounsaturated fats
Polyunsaturated fats
The more saturated the fat or the longer the carbon chains, the harder the fat is at room temperature.
Beef suet vs. vegetable oil

9. Amphipathic molecules
Amphipathic molecules “ both feeling”
one end is hydrophobic
one end is hydrophilic
Detergent molecules are like this
Polar end mixes with water
Hydrophobic end mixes with grease
Substitute a phosphate group for one fatty acid chain of a triglyceride: phospholipid

10. Hydrophilic portions associated with water.
Hydrophobic portions avoid water by associating with each other.

11. Phospholipids are amphipathic
Hydrophilic “head” group
Hydrophobic “tails”

12. Steroid are lipids
Cholesterol is an important part of your cells, but too much in your blood vessels is BAD.

13. Steroids Lipids with a different structure Based on cholesterol
In food and made by the liver
Vitamin D, steroid hormones, and bile salts
Includes “anabolic steroids”, source of controversy in the sports world

14. Hormones are messenger molecules your body makes.
“Steroid hormones” are chemically related to cholesterol.

15. A lipid polymer: a biodegradable plastic
made by bacteria.

16. Inclusions of PHB in a bacterial cell

17. Proteins Contain C, H,O and N (nitrogen)
Made up of 20 different amino acids
Amino group – NH2
Makes it a base
Carboxyl (acid) group – COOH
Makes it an acid
Side chain or R group
Linked by peptide bonds

20. Peptide Bond: joins two amino acids together.
Many amino acids joined: polypeptide or protein.

21. Proteins: important and abundant
Proteins make up structural and functional molecules within the body.
Enzymes: the tools of the cell.
About 50% of the dry weight of cells
Structure of protein is directly determined from the DNA sequence.

22. Proteins: 4 levels of organization
Primary structure
The particular amino acids and their order
Secondary structure – folding in alpha helices or beta sheets
Tertiary structure
The 3D shape of the protein, critical for function
Quaternary structure
Multiple proteins work together (hemoglobin)

23. Primary and secondary structure

24. Tertiary and quaternary structures

25. The 3D shape of a protein is critical for its function.
If a protein is subjected to high or low temperatures, changes in pH or ion concentration the protein denatures, or changes shape and becomes nonfunctional.

26. From molecules to cells
We study the 4 classes of biological molecules because that’s what cells are made of.
Cells take in these molecules, digest them
Convert them polymers into monomers
Rebuild polymers according to directions in cell’s DNA
As we study the cell, note what the cells are made of.

27. Cell Theory All organisms are composed of one or more cells
Cells are alive, and are the basic living unit of organization of all organisms
All cells come from other cells

30. Every cell has three main parts:
Plasma (cell) membrane – a boundary that separates inside of cell from external environment.
A set of genetic instructions In eukaryotes this is in the Nucleus; in prokaryotes there is no membrane, stays in a section of the cell is called the nucleoid.
A cell body - the cytoplasm; gel-like substance within the cell membrane.

31. Cells are measured in micrometers or microns.
Eukaryotic cells are bigger and more complex than prokaryotic cells.
Advantages of being made of cells:
Specialization
Surface area
A multicellular organism can survive the loss of single cells.

32. Plasma Membrane
The plasma membrane does more than just separate the outside of a cell from the inside; it controls what enters and leaves the cell, and much of the activity within the cell.
Most of the cell membrane is made of a phospholipid bilayer. Amphipathic molecule – phosphate heads on the outside and inside, and fatty acid tails in the middle.

34. The membrane is selectively permeable – it allows fat soluble substances to pass through (such as steroid hormones) and some other small, uncharged molecules.
Cholesterol is a large molecule, and helps to stabilize the membrane in animals.
Plants use phytosterol.

36. Fluid mosaic model - proteins float like
icebergs in a sea of phospholipids.
Proteins can be integral proteins – go all the way through the membrane, or may be
peripheral proteins -bound to the inside or outside membrane.

38. Integral Proteins can be channels or transporters.
Peripheral proteins can be receptors, or can be cell identity markers or recognition proteins that identify a cell as “self” (like UPC codes). These are often glycoproteins.
They may also mark worn out red blood cells or cells that have been infected with a virus.

39. All cells have a plasma membrane
Some cells, such as bacterial, fungal and plant cells, also have a cell wall.
The organelles in a eukaryotic cell all have membranes around them.
These membranes are very similar to the plasma membrane: lipid bilayer with proteins floating in it.

41. Cytoplasm refers to cytosol plus organelles and inclusions.
cytosol - contains proteins, enzymes, nutrients, ions, and other small molecules
organelles -“little organs” - highly organized structures with characteristic shapes that are specialized for specific cellular activities.
inclusions - are temporary structures in the
cytoplasm that contain secretions and
storage products of the cell.