NAS 2 CHALLENGE CORE EXAMS SET 2025/2026 ANSWERS
AND QUESTIONS GRADED A+
✔✔describe how enzymes catalyze chemical reactions - ✔✔an enzyme will grab on
(bind) to one or more reactant molecules. These molecules are the enzyme substrates.
In some reactions, one substrate is broken down into multiple products. In others, two
substrates come together to create one larger molecule or to swap pieces. Enzymes
lower activation energy required for reaction to proceed
✔✔Identify water's role in life - ✔✔Water has important roles and functions in chemistry,
biochemistry, and biology due to its diverse properties. Without it, there would be no life
on earth.
✔✔define pH; identify values on the pH scale - ✔✔pH: a measure of acidity; measure of
hydrogen ion concentration
-if pH is above 7: basic/alkaline
-if pH is below 7: acidic
-if pH is 7: neutral
✔✔Define organic compound - ✔✔A compound that contains carbon
✔✔Define monomer - ✔✔Small building blocks to make polymers
✔✔Define polymer - ✔✔Long molecules made up of many similar building blocks
(monomers)
✔✔identify the four major groups of organic compounds - ✔✔-carbohydrates, lipids,
proteins, and nucleic acids
✔✔describe protein three-dimensional structure and its role in protein function -
✔✔tertiary, functional protein, either globular or rod like. Fibrous or globular to provide
structure
✔✔Identify specific types of organic compounds and their functions - ✔✔-Nucleic acids:
information molecule, molecule of heredity, director of metabolism involved in protein
synthesis, immediate source of energy for cellular work
-Lipids: components of membranes, long term energy storage, insolation
-Carbohydrates: short term energy source, transport form in animal, long term energy
storage
-Proteins: organic catalyst, digestive enzymes, structural protein in hair, structural
protein in skin
, ✔✔list all the components of the cell theory - ✔✔-All living organisms are composed of
cells. They may be unicellular or multicellular
-the cell is the basic unit of life
-cells arise from pre-existing cells
✔✔identify cell organelles and their functions - ✔✔-a subcellular structure that has one
or more specific jobs to perform in the cell, much like an organ does in the body
-nuclei: stores genetic information
-Mitochondria: produce chemical energy
-Ribosomes: assemble proteins
✔✔what are the three main parts of the cell cycle - ✔✔interphase, mitosis, and
cytokinesis
✔✔Interphase - ✔✔1. G1 )growth 1): The cell grows to accommodate new genetic
information
2. S (synthesis): the cell dupplicates its DNA for the two daughter cells
3. G2 (growth 2): the cell grows once again for there to be enough
✔✔Mitosis - ✔✔1. Prophase: chromatin is organized into chromosomes, two
centrosomes move to the poles of the cells, and the nuclear envelope breaks down
2. Prometaphase: the nuclear envelope is gone, the spindle fibers start to form, and the
chromosomes start to move towards the equator of the cell
3. Metaphase: the chromosomes align in the middle of the cell
4. Anaphase: the chromosomes are split apart into chromatids by the spindle fibers and
are starting to be pulled to opposite poles
5. Telophase: the chromatids are enveloped in a new nuclear envelope in the two new
daughter cells making two separate nuclei
6. Cytokinesis: the cells cytoplasm splits and forms the two new daughter cells which
are identical to the parent cell. Both have their own nucleus and DNA
✔✔define mitosis and its role in cell biology - ✔✔the process where a single cell divides
resulting in generally two identical cells, each containing the same number of
chromosomes and genetic content as that of the original cell
✔✔Identify the steps of mitosis and cytokinesis - ✔✔-Prophase: chromosomes recruit
condensin and begin to undergo a condensation process that will continue until
metaphase
-Prometaphase: begins with the abrupt fragmentation of the nuclear envelope into many
small vesicles that will eventually be decided between the future daughter cells
-Metaphase: chromosomes assume their most compacted state, when the centromeres
of all the cells chromosomes line up at the equator of the spindle
AND QUESTIONS GRADED A+
✔✔describe how enzymes catalyze chemical reactions - ✔✔an enzyme will grab on
(bind) to one or more reactant molecules. These molecules are the enzyme substrates.
In some reactions, one substrate is broken down into multiple products. In others, two
substrates come together to create one larger molecule or to swap pieces. Enzymes
lower activation energy required for reaction to proceed
✔✔Identify water's role in life - ✔✔Water has important roles and functions in chemistry,
biochemistry, and biology due to its diverse properties. Without it, there would be no life
on earth.
✔✔define pH; identify values on the pH scale - ✔✔pH: a measure of acidity; measure of
hydrogen ion concentration
-if pH is above 7: basic/alkaline
-if pH is below 7: acidic
-if pH is 7: neutral
✔✔Define organic compound - ✔✔A compound that contains carbon
✔✔Define monomer - ✔✔Small building blocks to make polymers
✔✔Define polymer - ✔✔Long molecules made up of many similar building blocks
(monomers)
✔✔identify the four major groups of organic compounds - ✔✔-carbohydrates, lipids,
proteins, and nucleic acids
✔✔describe protein three-dimensional structure and its role in protein function -
✔✔tertiary, functional protein, either globular or rod like. Fibrous or globular to provide
structure
✔✔Identify specific types of organic compounds and their functions - ✔✔-Nucleic acids:
information molecule, molecule of heredity, director of metabolism involved in protein
synthesis, immediate source of energy for cellular work
-Lipids: components of membranes, long term energy storage, insolation
-Carbohydrates: short term energy source, transport form in animal, long term energy
storage
-Proteins: organic catalyst, digestive enzymes, structural protein in hair, structural
protein in skin
, ✔✔list all the components of the cell theory - ✔✔-All living organisms are composed of
cells. They may be unicellular or multicellular
-the cell is the basic unit of life
-cells arise from pre-existing cells
✔✔identify cell organelles and their functions - ✔✔-a subcellular structure that has one
or more specific jobs to perform in the cell, much like an organ does in the body
-nuclei: stores genetic information
-Mitochondria: produce chemical energy
-Ribosomes: assemble proteins
✔✔what are the three main parts of the cell cycle - ✔✔interphase, mitosis, and
cytokinesis
✔✔Interphase - ✔✔1. G1 )growth 1): The cell grows to accommodate new genetic
information
2. S (synthesis): the cell dupplicates its DNA for the two daughter cells
3. G2 (growth 2): the cell grows once again for there to be enough
✔✔Mitosis - ✔✔1. Prophase: chromatin is organized into chromosomes, two
centrosomes move to the poles of the cells, and the nuclear envelope breaks down
2. Prometaphase: the nuclear envelope is gone, the spindle fibers start to form, and the
chromosomes start to move towards the equator of the cell
3. Metaphase: the chromosomes align in the middle of the cell
4. Anaphase: the chromosomes are split apart into chromatids by the spindle fibers and
are starting to be pulled to opposite poles
5. Telophase: the chromatids are enveloped in a new nuclear envelope in the two new
daughter cells making two separate nuclei
6. Cytokinesis: the cells cytoplasm splits and forms the two new daughter cells which
are identical to the parent cell. Both have their own nucleus and DNA
✔✔define mitosis and its role in cell biology - ✔✔the process where a single cell divides
resulting in generally two identical cells, each containing the same number of
chromosomes and genetic content as that of the original cell
✔✔Identify the steps of mitosis and cytokinesis - ✔✔-Prophase: chromosomes recruit
condensin and begin to undergo a condensation process that will continue until
metaphase
-Prometaphase: begins with the abrupt fragmentation of the nuclear envelope into many
small vesicles that will eventually be decided between the future daughter cells
-Metaphase: chromosomes assume their most compacted state, when the centromeres
of all the cells chromosomes line up at the equator of the spindle
