Review for BCT
Landa, 2012
Six elements needed for life
• CHNOPS
• Remember these are in the Carbon (CO2) , water (H2O), nitrogen (N2
and NO2 and NO3) cycles. P an S are small
Molecule
Two or more ATOMS bonded together
O2 and CO2 are molecules as is H2O
When two or more DIFFERENT elements are bound together  its
called a compound.
Organic Molecules
• In non-living things: C and H
• In living things: C, H , O
Macromolecules (Organic)
Class name
Element Function
s
Carbohydrate C, H, O Monosaccharides: simple
fast energy
Polysaccharides: Short term
energy storage
Examples
Structure:
Carbs can be single
carbon rings (mono.)
or chains of many rings
linked together (poly.)
Lipid
C, H, O
Long term energy storage
Insulation
Waterproofing (plants)
Mono: sugars
(glucose,
fructose)
Poly: starch, fiber
(cellulose)
Fats, waxes, oils
Protein
C, H, O,
N, S
Speeds up chemical
reactions,
Fights infection
Builds structures
Sends chemical messages
Enzymes
Antibodies
Cartilage
Hormones
NOT a chain of
repeated units
Does not form
polymers
Proteins are large
chains of amino acids
that need to be folded
into a specific shape to
work.
Macromolecules (Organic)
Nucleic C, H, O, Stores information
Acids
N, P
on how to make
proteins,
Makes up our
genes (single
recipes for a
protein)
DNA –
master copy
of all genes
RNA – temp
copy of single
gene
Nucleic acids are
chains of
nucleotides
Sequence of
nucleotides
(ATGC) determines
information
Enzymes
• What class of organic compounds?
• Proteins
• Job
• Speed up chemical reactions by lowering the amount of energy needed
• Conditions which affect an enzyme.
• Temperature, pH, concentration
Enzymes and Structure
• Enzymes (folded chains of amino acids) must
• be folded in a specific way (correct 3D structure) in order for their substrate
(the molecule they are breaking down/linking together) can fit together with
the enzyme
Processes requiring enzymes
• ALL chemical process in a living thing require enzymes
• Examples:
photosynthesis, digestion, cell respiration, mitosis, meiosis.
Replication, transcription, translation…..
Homeostasis
• stable internal environment that is regulated and maintained
regardless of what is going on outside the cells/body
• Three conditions that must be maintained
• Temperature, pH, chemical levels (glucose in the blood, sodium, etc)
Functions of Water
• Temperature regulation – sweat
• Lubrication – joints
• Transportation of nutrients – blood
• Senses -in vision/taste/smell/hearing
• Medium – for reactions
Regulating flow in/out of cell
• Cells regulate the flow of molecules in and out of the
cell using the CELL MEMBRANE (PLASMA
MEMBRANE).
•
• __DIFFUSION____ is the process that moves solutes
from high concentration to low concentration.
• ___OSMOSIS____ is the process that moves water
from hypotonic (low solute/high water) areas to
hypertonic (high solute/low water) areas
• ____ACTIVE TRANSPORT______________ is a process
that requires energy to move charged ions through the
membrane.
How does the membrane control flow?
• Depends on the size, charge and solubility (polar or nonpolar) of the
substance.
• Small, uncharged and non-polar chemicals dissolve easily (diffusion/passive
transport)
• Large, charged and polar molecules need help of a transport protein and/or
energy (facilitated diffusion or active transport)
How are different molecules used?
• Sugars are used by the ____mitochondria__ for cell respiration
• Proteins are broken down into subunits called ____amino
acids______ and used to build new proteins
Cells are made of:
• many small structures called ___organelles______________ each of
which has a specific job. List several jobs performed by the parts of
the cells:
When do Cells Divide?
• Growth and reproduction
• Repair injury
• Replace dead cells
Replication and DNA
• How do cells ensure that the new cells will have all the same
information that the old cells do?
• Copy the DNA using DNA replication
Identical DNA..but different cells????
• If the DNA is identical, how do we get specialized cells?
• can use different sets of the genes (within the same DNA to make different
proteins.
• Analogy: two people with the same cookbook can have different dinner
parties just by making different recipes.
• The process by which cells become specialized is called
_differentiation_
Why don’t cells get smaller as they divide?
• Because they GROW!!!!!
• After fertilization, what happens to a zygote?
• Must begin to divide through mitosis.
• How do cells differentiate?
• They “move around” cells in different chemical environments have different
genes activated (turned on).
• What happens if early cells in the embryo separate? IDENTICAL
TWINS
Mitosis and Meiosis
• Mitosis
• Happens when we need more body cells
• Produces two IDENTICAL cells
• Meiosis:
• Happens when we make reproductive cells
• Produces different cells (due to crossing over/genetic recombination) with ½
as many chromosomes as a body cell.
# of Chromosomes
• Body (Somatic) Cells
• Reproductive (Gamete) Cells
• ½ as many chromosomes as body cells
• Will fuse with another reproductive cell during fertilization (embryo now has
cells that has a complete set (2N) of chromosomes).
If mistakes during cell division occur
• During meiosis, a mistake would lead to a defect in the entire body of
an offspring.
• During mitosis, a single body part will probably be affected
Stem cells vs. Regular body cells
• Stem cells are not specialized (undifferentiated) and have the
capacity to differentiate into any type of cell.
• Body cells are already specialized and can only produce one type of
cell
Stem cells
• Mostly in embryonic tissue
• Some partially differentiated stem cells are found in body parts (ie
bone marrow)
• Potential to cure/prevent disease
• if we can learn how to direct stem cells to become specific cell types we might
be able to “grow” organs and repair spinal cord injuries.
Disrupting Normal Body Functions
• The structure of the body is necessary to maintain proper function of
the body. Damaging cells, organs and organ systems all have a
significant impact on how the organism as a whole functions. For
each of the following describe how it disrupts the normal functions of
the body as well as possible causes.
Disruption: Mutation
• change in the DNA;
• changes the recipe for the protein; protein may or may not work
properly;
• Example
• : defective enzyme = lactose intolerance
Pathogens
• bacteria and viruses;
• destroy cells or compete with our cells for nutrients in our body;
throw off internal homeostasis
Drugs/Poisons
• can alter the effectiveness of proteins in the body and prevent them
from doing their job;
• can disrupt homeostasis
Sample Problems
• Many diseases are caused when the body cannot digest particular
molecules in our diet. For example, Lactose intolerance is caused
when individuals cannot digest the sugar found in milk. What type of
molecule is a person missing if they are lactose intolerant?
•
•
•
•
Lipid
Monosaccharides
Nucleic Acids
Proteins
Problem 2
• Which of the following is NOT made of a long chain of repeating units
called monomers?
•
•
•
•
Lipid
Carbohydrates
Nucleic Acids
Proteins
Problem 3
• The information on how to make _____________________ is stored
in the _______________________.
•
•
•
•
Carbohydrates; Proteins
Proteins; Nucleic Acids
Nucleic Acids; Proteins
Proteins; Carbohydrates
Problem 4
• The MOST essential inorganic molecule for all living things is
_______________.
•
•
•
•
CO2
Sugars
Water
Oxygen
Problem 5
• The human body can make certain amino acids, but has to get others
from their diet. Lacking certain amino acids will interfere with your
body’s ability to make which of the following?
•
•
•
•
Lipid
Carbohydrates
Nucleic Acids
Proteins
Problem 6
• The body can extract energy from several different types of
molecules. Which one of the following provides SIMPLE FAST energy?
•
•
•
•
a. Monosaccharides
b. Lipids
c. Polysaccharides
d. Proteins
Problem 7
• Which of the following best explains why enzymes are necessary for
many cellular reactions?
•
•
•
•
A. Enzymes supply the oxygen necessary for the reactions.
B. Enzymes change reactants from solid to liquid during the reactions.
C. The reactions take up too much space in the cell if enzymes are missing.
D. The reactions are too slow to meet the needs of the cell if enzymes are
missing
Problem 8.
• Michelle is working in a lab. She is trying to use an enzyme to digest
starch into single monosaccharides. She adds starch to a tube and
then adds the enzyme. She knows that heat helps chemical reactions
so she places the tube on a hot plate and waits for a reaction. After
10 minutes nothing has happened. What went wrong?
•
•
•
•
Michelle added the wrong enzyme
Starch cannot be broken down into monosaccharides
The heat probably denatured the enzyme
10 minutes is too short, you need to wait for hours for enzymes to work
Problem 9.
• If an animal cell is placed in distilled water it may swell and burst. The
bursting of the cell is a result of which process?
•
•
•
•
Enzyme activity
Active transport
Osmosis
Respiration
Problem 10.
• Joe is studying different types of cells. He notices cells all have a
unique shape and sometimes even have special structures that aren’t
found in other cells. Which of the following would be the best
conclusion for Joe to make about his observations?
a. Some of the cells he is examining are mutated
b. Different cell types are specially adapted to work for specific organisms
c. Every different species has a different type of cell.
d. He must be looking at prokaryotic and eukaryotic cells.
Problem 11.
• The body as well as individual cells, is in charge of keeping
homeostasis. Which of the following could be the result of the body
failing to regulate a stable internal environment?
•
•
•
•
Diabetes
Dehydration
Fever
All of the above
Problem 12.
• Which two processes must happen before a cell goes through
mitosis?
•
•
•
•
The DNA must replicate and the chromosomes must separate
Two cells must form and the cells must grow
Cells must grow and DNA must replicate
Cells must divide and the DNA must replicate
Problem 13.
• DNA is folded into ___________ during mitosis and then unraveled
again at the end.
•
•
•
•
Proteins
Chromosomes
The nucleus
RNA
Problem 14.
• Which of the following can happen if cell division is not regulated
properly?
•
•
•
•
Diabetes
Cystic fibrosis
Cancer
Influenza
Problem 15.
• Normal cell division is involved in all of the following EXCEPT:
•
•
•
•
Repair of an injury
Growing
Making reproductive cells
Protein synthesis
Problem 16.
• Neurons, cells in the nervous system, and skin cells are very different.
They have a different shape, different function and are even found in
different places in the body. BUT upon close inspection, neurons and
skin cells have the exact same set of DNA. What causes all the
differences?
• In reality their DNA is different it only looks the same.
• They have the same DNA but access different genes to make different
proteins.
• Neurons don’t use their DNA
• Skin cells are actually dead cells.
Problem 17.
• Place the following stages in the order that they happen:
a. Fertilization  mitosis  differentiation  organ formation
b. Fertilization  differentiation  mitosis  organ formation
c. Mitosis  organ formation  differentiation  fertilization
d. Fertilization  differentiation  organ formation  mitosis.
Problem 18.
• The body cell of a carrot has 18 chromosomes. That means that the
carrot’s reproductive cells will each have _________ chromosomes
and a carrot zygote will have _________________ chromosomes.
a. 18; 18
b. 18; 36
c. 9; 9
d. 9; 18
Problem 19.
• A doctor performs amniocentesis on an embryo to find that it
contains an extra chromosome. Which is a possible diagnosis for the
baby?
•
•
•
•
Cancer
Down Syndrome
Influenza
Color blindness
Problem 20
• A young patient is diagnosed with the genetic disorder, Lactose
Intolerance, which results in the inability to digests milk products due
to a missing enzyme called lactase. What is most likely the cause of
lactose intolerance in this patient?
a. The patient is allergic to milk.
b. The patient stopped consuming milk products.
c. A disease destroyed the lining of the digestive tract.
d. A mutation occurred in the gene that is responsible for producing lactase.
Problem 21.
• Which of the following diseases/disorders is contagious?
a. Cancer
b. Strep throat
c. Color blindness
d. Down syndrome
Problem 22.
• Which of the following diseases/disorders is heritable (inherited)?
•
•
•
•
Cancer
Strep throat
Color blindness
AIDS
Problem 23.
• Disease, in general, can basically be defined as:
a. When our bodies are infected with foreign pathogens.
b. When mutations disrupt our ability to make proteins.
c. When organs are not formed properly
d. When an imbalance is created that prevents our body from functioning
normally.