BIOE 1010 Exam 1 Study Guide
Cells-the fundamental units of life:
∙ Types of Cells:
o Eukaryotic Cells:
▪ Have a distinct nucleus
▪ Animal cells and plant cells
o Prokaryotic Cells:
▪ No nucleus
*Water makes all of the complex chemical reactions of life possible.
∙ More than 2000 chemical reactions take place in a cell every second; many of them are mutually incompatible.
∙ Cells developed strategies to keep reactions isolated and organized in separate compartments.
∙ In the cell there are membrane-enclosed compartments with specific functions. We also discuss several other topics like How much light bends when it hit a different substance depends on the refractive indices of the media forming the interface?
Don't forget about the age old question of What determines if an individual will be male or female and is located on the y chromosome
∙ Examples of cell types:
o Cardiac muscle cells (cardio myocytes): responsible for heartbeat o Endothelial cells: line and protect the lumen of blood vessels o Fibroblasts: synthesize proteins and are responsible for scar tissue o Red blood cells: transport and deliver oxygen to the tissues. Their
shape provides a larger surface area so they can carry more oxygen.
o White blood cells: protect the body against infections
o Neurons: the core components of the nervous systems
If you want to learn more check out What is the debate of nature vs nurture?
o Chondrocytes: cells in cartilage
∙ Looking at living cells:
o Light Microscopy: magnifies cells up to 1000x and resolves details as small as 0.2 um.
▪ Can see no internal details
o Florescence Microscopy: cells are treated with fluorescent dyes, which absorb light at one wavelength and emit it at another, longer wavelength.
▪ Contains two filters
o Confocal Microscopy: builds an image by scanning the specimen with a laser beam
▪ Generates a sharp 3D image
▪ Florescent with specific details
Don't forget about the age old question of What are the disadvantages of transmission electron micrscopy?
o Transmission Electron Microscopy: uses a beam of electrons instead of a beam of light and magnetic coils. The specimen in stained with electron dense heavy metals that absorb electrons. ▪ Can resolve details as small as 2 nm
▪ Can even see a portion of a long DNA molecule
▪ Sample has to be at a very low temp
▪ Has to be used in an vacuum
We also discuss several other topics like What is nuclear magnetic resonance used for?
o Scanning Electron Microscopy (SEM): the specimen is covered with a film of heavy metal and is scanned by a beam of electrons. ▪ Creates a 3D image
▪ Can resolve details between 3-20 nm
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How big is a cell? 5-20 um
Proteins: structure and functions
∙ Matter is made of combinations of elements
∙ Elements are substances that cannot be converted into other substances ∙ An atom is the smallest particle of an element that still remains its distinctive chemical properties.
∙ A molecule is a particle formed by the chemical union of two or more atoms. ∙ To achieve a complete outermost shell (the electron configuration of noble gases), unstable atoms tend to gain, lose, or share valence electrons with other atoms participate in chemical reactions and form molecules. ∙ The outermost electrons determine how atoms interact
∙ Sharing of electrons: covalent bonds
∙ Transfer of electrons: ionic bonds
∙ Common biological functional groups:
∙ Proteins are long chains of amino acids and account for 20% of our bodies. ∙ Amino acids are grouped according to whether R is polar (hydrophilic) or non polar (hydrophobic).
∙ Amino acid molecules react and form peptide bonds.
∙ Three amino acids joined by peptide bonds and form a tripeptide. ∙ Polypeptides = Proteins
∙ The 4 levels of organization:
o Primary Structure: the sequence of amino acids that make up the polypeptide chain
o Secondary Structure: can take the form of an alpha-helix or a beta-sheet which are maintained by hydrogen bonds between amino acids. o Tertiary Structure: the folding and bonding of the secondary structure. o Quaternary Structure: occurs as a result of interactions between two or more tertiary subunits.
∙ An oligomeric protein is a complex of more than 1 chain that interact with each other.
∙ When the protein folds into its specific 3D conformation amino acids which belong to different regions of the polypeptide chain are brought together to form a cavity with a unique geometry (bonding site).
∙ Binding sites allow a protein to interact with its specific ligand.
∙ Protein Classification (by function):
o Structural: collagen, elastin
o Chemical Messengers: hormones, growth factors
o Transport: hemoglobin, myoglobin, lipoproteins
o Contractile: actin, myosin
o Protection: thrombin. Fibrinogen, antibodies
o Signaling: receptors
o Cell Adhesion: integrins
o Catalytic: enzymes
∙ Enzymes are the most highly specialized proteins
o They catalyze the conversion of substrate molecules into products o Are not consumed by the reactions they catalyze
∙ Active Catalytic Sites: pockets lined with amino acids that binds the substrate with great specificity and catalyze their chemical transformation.
∙ Induced-fit Model: both enzyme and substrate undergo dynamic conformational changes upon binding.
Carbohydrates and Cell Metabolism:
∙ Carbs contain carbon, hydrogen, and oxygen
∙ They are the most abundant biomolecules on earth
∙ The main energy source for the human body
∙ Protect the cell form mechanical and chemical damage
∙ Absorb water-lubricate skeletal joints
∙ Participate in cell-cell recognition and adhesion processes
∙ Monosaccharides: the simplest type of sugars
∙ Pentoses- contain 5 carbons
∙ Hexoses- contain 6 carbons
∙ Open-chain structures: contain many hydroxyl groups and a carbonyl group (aldehyde or ketone)
∙ Ring/Cyclic structures form in water.
∙ Disaccharides: two monosaccharides covalently linked ( glycosidic
∙ Examples: Sucrose (table sugar) and Lactose (milk sugar)
THIS DIAGRAM WILL BE ON EXAM!
KNOW WHAT THE GLYCOSIDIC BOND
∙ Polysaccharides: polymers consisting of chains of monosaccharide
▪ Glycogen (Poly glucose): the main storage
polysaccharide of animal cells, especially abundant in
the liver and skeletal muscle.
Energy and Cell Metabolism:
∙ To go from the building blocks to larger units, cells need
CATABOLISM WILL BE ON THE EXAM!
∙ Anabolism: biosynthesis of cell specific molecules using the energy harnessed form catabolism
∙ Catabolism: breakdown of food molecules generating energy and small molecules (building blocks)
∙ Energy is released by gradual oxidation of sugars and fats. ∙ Energy is transferred to carrier molecules (ATP and NADH) which store it temporarily in energy-rich bonds.
∙ ATP contains two high energy bonds.
∙ ATP provides the energy for synthesis of proteins, nucleic acids, fats, etc.
∙ The 2 types of reactions (releasing and requiring energy) are coupled by enzymes in many steps.
∙ In the cell, groups of enzymes work together: the product of one enzymatic reaction becomes substrate for the next one. This is called a metabolic pathway.
∙ Glycolysis occurs in the cytosol (cytoplasm). The first half of glycolysis uses 2 ATP but it gains 2 NADH molecules and 4 ATP in the end.
∙ The difference between NAD+ and NADH is NADH has an extra hydrogen bond and two more electrons than NAD+.
∙ ATP synthesis takes place in the mitochondria.
∙ Cells form ATP by complete oxidation of nutrient molecules in many small steps so that most of the energy released can be stored.