L2: THE BUILDING BLOCKS OF LIFE Flashcards
What is an atom?
An atom is the smallest unit of an element that has the chemical characteristics of that element.
What are the subatomic particles in an atom?
Protons (positively charged), electrons (negatively charged), and neutrons (neutral).
How many natural chemical elements are there?
There are 92 natural chemical elements.
Why do elements form bonds?
Elements form bonds to become stable by filling their outer electron shells.
How do atoms achieve stability?
Atoms achieve stability by sharing or transferring electrons with other atoms.
What is a covalent bond?
A covalent bond is a chemical bond formed when atoms share electrons.
How do hydrogen atoms form bonds?
Hydrogen atoms form covalent bonds by sharing electrons to fill their outer shell.
What are non-covalent bonds (NCBs)?
NCBs are weaker bonds that form between molecules or within molecules.
What type of molecules form hydrogen bonds?
Polar molecules, like water, form hydrogen bonds.
Why is water polar?
Water is polar because oxygen has a slight negative charge, and hydrogen has a slight positive charge.
How does the ionic bond in salt work?
Sodium (Na+) loses an electron to become positive, and chloride (Cl-) gains an electron to become negative, forming an ionic bond.
What happens when salt dissolves in water?
The ionic bond between Na+ and Cl- breaks, and water molecules surround and interact with the ions.
What are the four major classes of chemical compounds found in living organisms?
Sugars, nucleotides, amino acids, and fatty acids.
What is the predominant element in compounds?
Carbon
What is the difference between a monomer and a polymer?
A monomer is a small molecule, while a polymer is a larger molecule made of many monomers joined together.
How many atoms do monomers typically have?
Monomers typically have 20 or fewer atoms.
What are monosaccharides?
Monosaccharides are simple sugars, such as glucose, composed of carbon, hydrogen, and oxygen
What is the ratio of carbon, hydrogen and oxygen?
1:2:1
What is a polysaccharide?
A polysaccharide is a long chain of monosaccharides, such as glycogen in mammals.
How are disaccharides formed?
Disaccharides are formed when two monosaccharides bond via dehydration (loss of water).
What is an example of a disaccharide?
Sucrose is a disaccharide formed from glucose and fructose.
What is the role of nucleotides?
Nucleotides make up DNA and RNA, storing genetic information and energy for cells.
What are nucleotides?
Nucleotides are organic compounds that consist of a 5-carbon sugar, a base (e.g., A, T, C, G for DNA), and a phosphate group.
What are amino acids? What do they consists of ?
Amino acids are the building blocks of proteins, each consisting of an alpha carbon, a carboxyl group (-COOH), an amino group (-NH2), and a side chain (R).
How many amino acids are there?
There are 20 different amino acids.
How do amino acids form proteins?
Amino acids are linked together by peptide bonds to form proteins (polypeptides).
What are fatty acids?
Fatty acids are long carbon chains ending in a carboxyl group (-COOH), and they are components of fats and lipids.
What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids have no double bonds and are solid at room temperature
Unsaturated fatty acids have one or more double bonds and are liquid at room temperature.
What are phospholipids?
Phospholipids are molecules made up of a hydrophilic head and two hydrophobic fatty acid tails.
How do phospholipids form the cell membrane?
Phospholipids arrange in a bilayer, with hydrophilic heads facing the water and hydrophobic tails facing inward, creating a barrier.
What does hydrophilic mean?
Hydrophilic means “water-loving” and describes molecules (like sugars and salts) that interact with water.
What does hydrophobic mean?
Hydrophobic means “water-fearing” and describes molecules (like fatty acids) that do not interact with water.
