Transcript Keystone Review Day 2

Keystone Review Day 3
WATER, MACROMOLECULES,
STRUCTURE/FUNCTION, ENZYMES
Structure and function are closely related!
Change the structure = cannot
function
Examples:
Red blood cells – sickle cell anemiaround shape allows them to fit
through blood vessels
Muscle cells – long and stretchy to
expand and contract for movement
Structure and function are closely related!
Nerve cells – Long extensions reaching
out to send/receive messages
Arteries- thick & muscular to pump blood
Alveoli- increase surface for gas exchange
in lungs
Microvilli (small hairs) in small intestines
to increase surface area for nutrient
absorption
Cellular organelles have different structures. Mitochondria, for example,
possess highly folded inner membranes in addition to their outer
membranes. Vacuoles, on the other hand, are only surrounded by a singlelayer membrane; they do not have an inner membrane.
Why do cellular organelles have different structures?
❧A. All of the organelles in a particular organism are identical, but
organelles in different organisms are unique.
❧B. Organelles that are less important to the cell have less sophisticated
structures.
❧C. The structures of cellular organelles are related to their functions.
❧D. The structure of a cellular organelle mimics the appearance of the
organism.
2.Cells can be divided into two main categories –
eukaryotic and prokaryotic.
A.Identify a structural difference between prokaryotic
cells and eukaryotic cells that is directly related to
their difference in size.
B. Based on the structural difference, explain why
prokaryotic cells can be much smaller than eukaryotic
cells.
Part A: Eukaryotes contain (1) organelles and are
able to store molecules in the cytoplasm, which
requires a larger cell to house the organelles,
whereas prokaryotes do not contain organelles
and consequentially can be smaller. Eukaryotes
many chromosomes whereas prokaryotes have a
single small circular chromosome.
Part B: Prokaryotes can be (1) smaller than eukaryotes
because they do not need more room to house
organelles or stored molecules. Cells must have a proper
amount of DNA to keep control of and provide
enzymes/molecules for the cell. Eukaryotes have (2)
large amounts of DNA to account for their larger
metabolic requirements due to their organelles and
general complexity whereas prokaryotes have minimal
DNA to account for the simple metabolic requirements
of the small organelle free cell.
Water Structure
• Water is a POLAR molecule
• Electrons are unevenly shared
between O and H (polarity)
• O = slightly negative
• H = slightly positive
• Polar covalent bonds between the
O & H WITHIN one molecule
• Hydrogen bonds between
multiple water molecules
Water Properties
1. Ice is less dense than
liquid water (expands)
 Due to hydrogen bonds
causing the to expand
 Causes lakes to freeze
only on the top (allows life to
survive winters)
2. Surface Tension
Water molecules are attracted to
one another  force pulls inward =
creating “membrane” on outside of
water molecules
Caused by Hydrogen bonds creating
a strong bond between molecules
Cohesion = water molecules
sticking to other water molecules
3. High Specific Heat Capacity
Water has a high specific heat
capacity
◦Can absorb large amounts of heat and
only raise temperate by a few degrees
◦Regulates the climate (keeps it a
moderate temp)
◦Organisms (mostly made of water)
regulate body temp in the same way
Water is the most abundant molecule found in living organisms. Most
mammals, in fact, are approximately 70% water by weight. About 2/3 of
this water is present inside cells. The other 1/3 is present outside cells
(blood plasma). Why is water so important to cells?
A. Water determines which proteins are translated from the cellular
DNA.
B. It is the main structural component found in plasma membranes and
cell walls.
C. Almost all the chemical reactions in life processes occur in solutions
with water.
D. Water is stored in the cells to be used when the organism gets thirsty.
Water has a high specific heat, which means that it requires a great deal of heat
to change its temperature. Which of the following helps support life on Earth
and is a result of water's high specific heat?
A. In freezing temperatures, ice rises to the top of lakes and provides an
insulating layer that keeps the rest of the water from freezing.
B. Water is part of a continuous cycle in which liquid water falls to the Earth's
surface, is evaporated back into the atmosphere, and condenses into clouds that
produce precipitation.
C. Water droplets tend to clump together in drops instead of spreading out in a
thin film, allowing it to move through the roots of plants and through blood
vessels in the human body.
D. The water that covers over 70% of the Earth's surface stabilizes the weather
and climate of the Earth.
The human body contains approximately 70% water by
weight. Water is found inside and outside of cells, and it
is able to carry nutrients into and around cells in
addition to carrying wastes away from cells. Why is
water able to do this?
A. Water is very acidic.
B. Water is able to dissolve many substances.
C. Water is a nonpolar covalent compound.
D. Water is an ionic solution.
The human body can properly function only within a
certain temperature range. This tendency toward
maintaining a stable internal environment is known as
homeostasis.
Which of the following substances is most important for
maintaining a stable thermal environment within the
human body?
A. Glucose
B. Marrow
C. Water
D. Insulin
Lakes and oceans are able to stabilize air and land temperatures
because
A. the water is able to release large amounts of heat into the air
when necessary.
B. the temperature of water changes significantly instead of the
temperature of the air and land.
C. the salt in the water bodies is able to absorb large amounts
of heat.
D. water is able to absorb large amounts of heat without
significantly changing its temperature.
Biochemistry
Carbon
- Basis of all organic compounds
- Unique because:
- Forms diverse structures
(rings, chains & branches)
- Can bond with itself
- Can make double or triple
bonds
- Can make 4 covalent bonds
Carbon
- Unique because:
- Can make 4 covalent bonds
Due to having 4 valence
electrons in outer electron
orbital (which holds a total of 8)
To become stable, it forms 4
covalent bonds (each bond = 2
e-) to have 8 electrons
Atoms of what element form the backbone of
large, complex molecules such as sugars and
fats?
A. Oxygen
B. Carbon
C. Sodium
D. Sulfur
All living organisms contain carbon atoms. Which of the
following is an important characteristic of carbon?
A. Carbon atoms can bond with any other atom, but they
cannot form bonds with other carbon atoms.
B. Carbon atoms are highly reactive and form unstable bonds
with any available atom.
C. Carbon atoms can bond with many other kinds of atoms to
form very stable molecules
D. Carbon atoms are very stable and do not easily form bonds
with other atoms
All living things contain carbon. Which of the following
statements are true about carbon atoms?
I. Each carbon atom can form single bonds with up to four
other carbon atoms.
II.Each carbon atom can form double bonds with up to
two other carbon atoms.
III.Carbon atoms can join together to form chains or rings.
IV. A single molecule of some compounds can contain
thousands of carbon atoms
A.II and III only
B. I and III only
C. I, II, III and IV
D. I, II and III only
Organic Compounds
Organic = biological; made of Carbon
Made of monomers & polymers
Monomers= Building blocks (subunits)
of polymers
Polymers- Large molecules made of
multiple monomers
Organic Compounds
To Make Polymers:
Condensation (dehydration) Synthesis
→ Attaching monomers together & forming water in
the process
To Break Polymers into Monomers:
Hydrolysis Reaction
→ Adding water to break the bonds between
monomers within the polymer
Organic Compounds
Dehydration Reaction → Making
polymers from monomers
Organic Compounds
Hydrolysis → Breaking Polymers
Organic
Compound
Function
Carbs
Energy & Cell Monosaccha Polysaccharid C H O
Wall
ride
e (starch)
Structure
(glucose)
Lipids
(Fats)
Cell
membranes
Reserve
energy
Cushion
Insulation
Monomer
Glycerol
Fatty Acids
Polymer
Triglyceride
Phospholipid
Atoms Present
CHO
Organic
Compound
Function
Proteins Enzymes
Structure
(muscles,
hair)
Hormones
Transport
Nucleic
Acids
Monomer
Polymer
Amino
Acids
Polypeptide/ C H O N S
protein
Genetic Info
Nucleotide DNA/RNA
Instructions for
making of
proteins
Atoms
Present
CHON
A polymer is a large molecule that forms when smaller
molecules known as monomers bond covalently in a
repeating pattern. There are many biological polymers
such as nucleic acids, proteins, and starches.
What are the monomer units that make up starches?
A. Amino Acids
B. Fatty Acids
C. Nucleotides
D. Glucose
Which of the following best describes a carbohydrate?
A.Carbohydrates always consist of a five-carbon sugar, a
nitrogenous base, and one or more phosphate groups and are
used to store genetic information.
B.Carbohydrates are organic macromolecules that are insoluble in
water and have the ability to store energy for extended periods
of time.
C.Carbohydrates are organic macromolecules that are made up of
carbon, hydrogen, and oxygen atoms and are used for energy
storage or as structural molecules.
D. Carbohydrates are composed of amino acid monomers and
are involved in cell signaling, cell transport, immune
responses, and the cell cycle.
Review Game!
Enzymes
-Proteins that act as catalysts →
speed up rate of reaction
- Enzyme is not changed or used
up
How does it work?
- Lowers the activation energy
(energy needed to start a
reaction)  less energy
absorbed
Enzymes
Lock & Key Theory
- Enzyme and its substrate fit like a
lock and key
** Shape is VITAL to enzyme
function. Change shape (structure)
→ change function (does not work)
- Denaturation → change enzyme’s
shape from excess heat or pH
- Enzymes function only at
certain temperatures/pH’s
(optimal)
- Excess temp or pH
changes shape of enzyme
→ makes it unable to
function.
1.Based on the figure, what do
you think happens to
enzyme X at 45 degrees?
a.It becomes more active
b.It becomes denatured
c.It runs out of substrate
d.None of the answers are
correct.
Temperature Enzyme A Enzyme B
What is the optimal
Rate of
Rate of
temperature for
Reaction Reaction
Enzyme B to function?
5°C
0.30
0.10
A. 15 ° C
15 ° C
0.50
0.20
B. 35 ° C
25 ° C
0.20
0.43
C. 25 ° C
35
°
C
0
0.60
D. 50 ° C
50 ° C
0
0.15
If the black line represents a reaction
without an enzyme and the red line
represents the same reaction with the
addition of an enzyme, what can be
said of the relationship between the
use of an enzyme and the energy of
the reaction?
A.
B.
C.
D.
Less energy is released by a reaction without an enzyme.
More energy is absorbed by a reaction with an enzyme.
Less energy is released by a reaction with an enzyme.
More energy is absorbed by reactions without an enzyme.
Catalase is an enzyme that is found
in all living tissues. Cells need
catalase in order to function
properly. Which of the following
statements can be inferred using the
above information?
A. Cells can function equally as well at all temperatures because enzymes are effective
at all temperatures.
B. Cells only function within a specific temperature range because enzymes only
function within a specific temperature range.
C. Cells only function within a specific pH range because enzymes only function within a
specific pH range.
D. Cells can function equally as well at all pH's because enzymes are effective at all
pH's
What can Tobin conclude about the
relationship between the enzyme
concentration and the reaction rate
in the presence of excess
molecules?
A. The experiment is invalid because it was performed in the presence of excess
molecules.
B. There is a direct relationship; as the enzyme concentration increases, the rate of
reaction increases.
C. There is no relationship between the enzyme concentration and the reaction
rate.
D.There is an inverse relationship; as the enzyme concentration increases, the
reaction rate decreases.