UNIT 1 - Cells, Water, and Buffers Flashcards
Define “biochemistry.”
Biochemistry is the application of chemisty to the biological process at the cellular and molecular level
Differences in Prokaryotes and Eukaryotes
Eukaryotic cells are larger and more complex, and include a nucleus and organelles. Eukaryotic cells organize DNA into long strands called chromosomes, while Prokaryotes are
Types of saccharides?
Mono, Di, Oligo (3-6) and Poly (7+)
Define “metabolic pathway.”
a set of actions or interactions between genes and their products that results in the formation or change of some component of the system
Which six elements make up 99% of the mass of living cells?
C, O, N, H, Ca, P
What are the four elements most commonly found in biomolecules?
C, O, N, H
List and describe the four main classes of biomolecules.
Lipids (Fatty Acids), Nucleic Acids (Nucleotides), Carbohydrates (monosaccharides), Proteins (Amino Acids)
How does the composition of the earth’s crust and living cells differ?
Silicon, Iron (Fe), Oxygen, and Aluminum (Al)
What is the function of the following organelle?
cytoskeleton
Structure and protection for the cell
What is the function of the following organelle?
mitochondria
ATP synthesis
What is the function of the following organelle?
ribosomes
Ribosomes synthesize proteins.
What is the function of the following organelle?
lysosome
Lysosomes are responsible for digestion.
What is the function of the following organelle?
Golgi apparatus
Golgi apparatus is involved in protein assembly and secretion
Where are sugars and fats digested in the cell?
In the cytoplasm, then once sufficiently broken down they are transported to the mitochondria for the krebs cycle and ETC to finish oxidation
List the differences between prokaryotic and eukaryotic cells in terms of the following:
nucleus
internal structures
cytoskeleton
DNA organization
Reproduction
Prokaryotes do not have a nucleus, nor organelles. Their DNA is circular, while eukaryotes are linear and wrapped around histones. Prokaryotes reproduce by binary fission, while eukaryotes undergo mitosis and meiosis. Prokaryotes don’t have a cytoskeleton, but some proteins
Using the concept of H‑bonding, explain how small items that are denser than water (e.g., a fine needle or a water bug) can remain on the surface instead of sinking.
Water is a mosaic structure in which ~ 90% of the H‑bonds are intact at any given moment. Therefore, water can be thought of as a semi‑solid as well as a liquid.
Why is pH important for molecules, in particular proteins?
formal charge changes based on pH which can affect the secondary, tertiary and quaternary structure formations.
Define the terms “acid” and “base.”
An acid is a substance with protons that can dissociate when dissolved in water. A base is a substance that can absorb protons when dissolved in water.
Explain the properties of weak acids and weak bases.
Weak acids do not lose protons as readily (H+) and weak bases do not absorb protons readily (OH−) when dissolved in water.
What is a buffer and why are buffers important?
A buffer is a weak acid. Buffers are important because they resist changes in pH by releasing protons to compensate for those “used up” or that have dissociated in reacting with hydroxyl ions (OH). Buffers provide or absorb protons as needed. They help to keep the H+ concentration, or pH, relatively constant.
Explain pKa and give an example to illustrate what this value means in terms of acids.
Like pH is to [H], it’s the negative log of the dissociation constant (Ka). High Ka = low pKa = low pH = strong acid.
