Bio 10 Exam 1
Osmosis can be defined as ________.
the diffusion of water across a selectively permeable membrane
Why is water considered a polar molecule?
the oxygen end of the molecule has a slight negative charge and the hydrogen end has a slight positive charge.
Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.
transport proteins; down
A fatty acid containing one or more double bonds is called______ and is __________ at room temperature?
unsaturated & Liquid
Relative to other substances, water tends to resist changes in temperature. Why?
water is highly cohesive
A dehydration reaction is the process in which __________.
water molecules are formed when polymers are synthesized from monomers
Which of these refers to atoms with the same atomic number but different atomic masses?
isotopes
As water freezes, ________.
its molecules move farther apart
example of protein
lactase
Steroids are in the class of molecules we call?
lipids
An animal cell placed in a hypertonic solution will __________.
lose water by osmosis and shrivel
what breaks down worn out organelles?
lysosomes
What carries instructions for making proteins from the nucleus into the cytoplasm?
mRNA
what are hollow rods that shape and support the cell
microtubules
Where in a cell is ATP made?
mitochondria
if placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference?
relative inelasticity and strength of the plant cell wall
One of the ways smooth endoplasmic reticulum (ER) differs from rough endoplasmic reticulum is that rough ER is covered by?
ribosomes
_____ are the sites of protein synthesis.
ribosomes
what type of fat only contain single bonds in their fatty acid tails?
saturated fat
Where is calcium stored?
smooth endoplasmic reticulum
Where are lipids made in the cell?
smooth endoplasmic reticulum (ER)
Example of carbohydrates
starch
Some tiny insects are able to walk on water. Why?
surface tension
Water is sometimes called the "universal solvent." Is that accurate?
For the most part. Water readily dissolves most substances, but not hydrophobic ones.
What modifies and packages proteins?
Golgi apparatus
what converts chemical fuel into ATP packets that can power the cell?
Mitochondrion
In order to have a positive charge, an atom must have______.
More protons than electrons
Isotopes of an element have the same number of _______ and different numbers of ________.
Protons and Neutrons
_________is used in all steps of protein synthesis and carries the genetic information of many viruses.
RNA
In salt, what is the nature of the bond between sodium and chlorine?
ionic
What is the term for an atom that is electrically charged as a result of gaining or losing electrons?
ions
what is the ideal osmotic environment for an animal cell?
isotonic environment
what type of solution will cause a plant cell to be flaccid (limp)?
isotonic solution
Which term is used to describe an animal's ability to survive if the cells are exposed to a hypotonic or hypertonic environment?
osmoregulation
A polypeptide is a long chain of amino acids bonded together by __________.
peptide bonds
what has a strong protective structure made from cellulose fibers?
plant cell wall
Both animal and plant cells accumulate water through osmosis when placed in hypotonic solutions. This causes the cells to swell. Why can plant cells better tolerate this?
plant cells have rigid cell walls that limit how far cells expand & prevent them from bursting
The _____ is a selective barrier, regulating the passage of material into and out of the cell.
plasma membrane
how are charges distributed on a water molecule?
The oxygen end is negative relative to the end with the two hydrogen atoms.
Water readily sticks to many other substances, a property called ______.
adhesion
Proteins are polymers constructed from ______ monomers?
amino acid
The building blocks of proteins are called __________.
amino acids
The simplest unit of matter that still retains the properties of an element is __________.
an atom
An ionic bond involves _____.
an attraction between ions of opposite charge
Atoms with the same number of protons but with different electrical charges _____.
are different ions
_____ is/are identical in structure to centrioles.
basal bodies
A substance that resists changes in pH is referred to as a(n) _____.
buffer
The large diversity of biological molecules depends on atoms of the element __________.
carbon
Plant cell walls consist mainly of __________.
cellulose
what regulates cell composition, creates internal pressure, and stores cell compounds?
central vacuole
What reaction links polymers to monomers?
dehydration reaction
The passive movement of molecules from an area of higher concentration to an area of lower concentration is called __________
diffusion
All lipids share this characteristic.
do not dissolve in water
Substances that cannot be broken down into other substances are called __________.
elements
lactase is an_____.
enzyme
Cells with a higher concentration of ions than the surrounding medium tend to ________.
expand
What is the main sugar used by cells for energy?
glucose
In the reaction glucose + fructose → sucrose + water, __________ is a reactant and __________ is a product.
glucose and water
Hydrocarbons are organic molecules that contain only __________.
hydrogen and carbon atoms
In osmosis, water moves across a selectively permeable membrane toward the __________ solution; that is, toward the solution with the __________ solute concentration.
hypertonic ... greater
in what type of solution will a plant cell lose water a plasmolyze?
hypertonic solution
what is the ideal environment for a plant cell?
hypotonic environment
what type of solution causes an animal cell to gain water, swell, and possibly burst?
hypotonic solution
What is the structure of a steroid?
-5 benzene rings -1 pentene ring
Relative to a pH of 7, a pH of 4 has a ________.
1,000 times higher H+ concentration
A single carbon atom can form a maximum of ________ covalent bond(s).
4
a single carbon atom can form a maximum of __________ covalent bonds.
4 covalent bonds
What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?
6
What is the pH inside most living cells?
7
An uncharged atom of mercury has an atomic number of 80 and an atomic mass of 200. This atom has ________ protons, _______ neutrons, and _________ electrons.
80, 120, 80
What name is given to bonds that involve the sharing of electrons?
Covalent Bonds
__________is the self-replicating material present in nearly all living organisms; it is the main constituent of chromosomes and the carrier of genetic information.
DNA
example of nucleic acid
DNA and RNA
Why is water polar?
Uneven distributions of charges
what makes food by converting light energy to chemical energy?
chloroplasts
Example of lipids
cholesterol
The _____ is composed of DNA and protein.
chromatin
___________are tightly coiled bundles of DNA and protein found in the nucleus of most living cells.
chromosomes
The tendency of water molecules to stick together is called __________.
cohesion
Water striders are common insects that can skip across the surface of ponds and streams. This lifestyle is enabled by water's _____.
cohesion and resulting surface tension
Substances that contain two or more elements in a fixed ratio are called __________.
compounds
Which of these is a type of chemical bond that involves the sharing of electrons?
covalent bond
The structural framework in a cell is the
cytoskeleton
What name is given to this reaction: galactose + glucose ---> lactose + water?
dehydration
The lower the pH of a solution, the ________.
more acidic the solution
what pH does a solution have when the OH and H ions are equal?
neutral
Carbon-12 and carbon-13 are different in the number of __________ they have.
neutrons
_________s the two-layered membrane that encases the nucleus of a eukaryotic cell, separating the nucleus from the cytoplasm.
nuclear envelope
A protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm is called a________.
nuclear pore
Ribosomal subunits are manufactured by the _____.
nucleolus
The round body that sits inside the nucleus of a eukaryotic cell and makes ribosomal subunits from proteins and ribosomal RNA is known as the__________.
nucleolus
The building blocks of nucleic acid molecules are called __________.
nucleotides
Where is the genetic information of the cell stored?
nucleus
_________is the most prominent membrane-bound organelle in eukaryotic cells, and it houses most of a cell's DNA.
nucleus
In an atom with a neutral overall charge, the number of protons is equal to the __________.
number of electrons