Unit 2 - Chemistry of Life Study Guide Flashcards
What is the difference between an organic molecule and an inorganic molecule?
Organic molecules contain Hydrogen and carbon while inorganic molecules don’t
How is an ionic bond created?
Transfer of electrons between ions
How is a covalent bond created?
two atoms share electrons (ex. the H and the O share electrons in H2O)
When is a hydrogen bond useful?
Causes high specific heat in liquids like water, which organisms can easily adapt to because of little temperature changes
Which bond type is strongest and most prevalent in nature?
Covalent bonds
What does it mean for a molecule to be polar?
Has a positive and negative atom; uneven distribution of charge
What are the characteristics of an enzyme?
Protein that speed up chemical reactions (catalyst) in our bodies by lowering the activation energy to build or break down substances. If exposed to extreme temperatures and pH, enzymes change shape making them unable to function (denatured enzyme).
Explain the lock and key model for an enzymatic reaction.
Models the enzyme-substrate interaction and shape
What is a high surface tension?
“Thin skin” that resists an external force. ex. when you hit the water it splashes rather than hitting it hard
What is pH?
Measure of how acidic or basic a substance is
What pH range denotes a base? An acid? A neutral?
Acid: 7-
Neutral: 7
Base: 7+
Why are buffers important to organisms?
Buffers neutralize the pH of substances to maintain homeostasis
What are the characteristics, element composition, and building blocks of a Carbohydrate?
Carbohydrates (sugars) are an organism’s main source of energy that is metabolized in cells to release energy either starches, sugars, or fiber (all commonly end in -ose). Monosaccharides are the monomer of carbs. Carbs are monosaccharides (simple sugars) if there is one glucose molecule, disaccharides if there are two glucose moleculers, and Polysaccharides (complex carbs) if there is many glucose molecules.
What are the characteristics, element composition, and building blocks of a Protein?
Proteins are long chains of amino acids, linked by peptide bonds (small proteins are called peptides). Proteins do many things like build tissues and make enzymes, regulated by cell DNA. Commonly end in ‘-ase’.
What are the characteristics, element composition, and building blocks of a Nucleic Acid?
Nucleic acids store genetic information for bodily functions. Nucleic acids are made up of nucleotides made of sugar molecules, a phosphate, and a nitrogen base. Living things have two types of nucleic acids: DNA and RNA. They differ in many ways like how DNA contains sugar deoxyribose while RNA contains sugar ribose.
What are the characteristics, element composition, and building blocks of a Lipid?
Lipids are an energy supply for cells including steroids, waxes, oils, and fats. Fatty acids are the monomers of lipids which have two types: unsaturated and saturated. Unsaturated fats have double bonds in their molecules, while saturated fats have no double bonds and should be avoided as they can cause health issues. In cells, fats form oil droplets called globules which store energy for the body.
What is the test used to indicate the presence of a starch? What does a positive test look like?
Lugol Iodine Solution tests the presence of starch; blue/black precipitate forms if positive
What is the test used to indicate the presence of a sugar? What does a positive test look like?
Benedict’s solution tests the presence of sugar; yellow/red if positive
What is the test used to indicate the presence of a protein? What does a positive test look like?
Biuret test tests the presence of protein; purple if positive
What is the test used to indicate the presence of a lipid? What does a positive test look like?
Brown bag test tests the presence of lipids; translucent if positive
What are the four categories of organic compounds?
- Nucleic Acids
- Proteins
- Carbohydrates
- Lipids
Why aren’t tests done to show the presence of nucleic acids?
All living organisms contain genetic material
Why do plants have waterproof leaves?
Plant cells contain lipids
Why don’t lipids dissolve in water?
Lipids aren’t polar molecules
What is water made up of?
1 oxygen atom (-negatively charged) + 2 hydrogen atoms (+positively charged) + combined by covalent bonds
Plants store glucose as _____
starch
What determines a protein’s job?
shape
What do buffers do in the human body?
Ensure the blood pH remains close to neutral
Why does water expand when frozen (ice floats on water)?
When water is frozen, the hydrogen bonds form ice crystals that are spread out and less dense
What types of molecules can water dissolve?
polar molecules; molecules with uneven distribution of charge
How does water aid in digestion and movement?
water is a lubricant (substance that reduces friction in the body)
Difference between a solute and solvent
Solute - dissolved in a solvent
solvent - dissolves a solute
(ex. in salt water, water is solvent, salt is solute
Hydrogen bond
weak bond between + charged Hydrogen atom and a - charged atom (ex. bond between two water molecules in H2O)
