FINAL Flashcards
What is not a characteristic of living things?
Conduction of Heat
Viruses present a challenge in determining what is either living or non-living because they…
Exhibit characteristics of life but only when they have infected a cell
What is one of Charles Darwin’s observations?
Many of the traits in an individual are heritable
What provides evidence of the common ancestry of all living things on Earth?
All cells store genetic information in DNA
What is a substance that cannot be broken down into other substances by a chemical reaction?
Element
If you change (add or subtract) the number of electrons in an atom, you create ____________.
an ion
What are the naturally occurring elements that make up 96% of the mass of an organism?
Oxygen, Hydrogen, Carbon, and Nitrogen
An _________ is the smallest unit of matter that still retains the properties of an ____________.
atom, element
If you change the number of protons in an atom, you create _________.
A different element
Which of the following best describes the relationship between the atoms described below?
Atom 1: Atom 2:
1 H 3 H
1 1
They are isotopes
The naturally occurring element Bromine has an atomic mass of 80 mass units (amu) and contains 45 neutrons. What is the atomic number of Bromine?
35
What does the chemical behavior of an atom depend on?
The electrons in the outer energy shell of the atom
In an atom, the electrons are arranged in distinct energy levels or shells. Electrons in shells that are farther away from the nucleus have ________ potential energy than electrons in shells that are closer to the nucleus.
more
A covalent bond is considered polar when…
one of the atoms sharing electrons is much more electronegative than the other atom
When are atoms most stable?
When the valence shell is completely filled with electrons
In a molecule of methane (CH4):
The bonds between C and H are covalent and the electrons are shared equally
What kind of atom is most likely to form an anion with a charge of -1?
One with a full valence shell of electrons.
The movement of water from the roots to the leaves in a tree is possible due to what property resulting from its molecular structure?
The cohesion between water molecules that results from hydrogen bonding
When heat is absorbed by liquid water, what will happen to individual water molecules?
hydrogen bonds between water molecules will be broken
Because of its ability to hydrogen bond to itself, the temperature of water changes _______ other substances when water absorbs heat.
less than
A mole of sucrose (sugar) and a mole of caffeine are equal in their…
number of molecules
the partial negative charge at one end of a water molecule in attracted to the partial positive charge of another water molecule. What is this attraction called?
a hydrogen bond
The mass of one molecule of sucrose is 342 mass units (amu). A mole of sucrose is equivalent to what?
342g
Which of the properties of water is extremely rare when compared to other substances?
Ice floats on water
An _________ is a substances that decreases the hydrogen ion [H+] concentration of an aqueous solution.
Base
What is the hydrogen ion concentration [H+] of a solution with a pH of 10?
10^-10 M
A given solution contains 0.001 (10^-3) moles of hydrogen ions [H+] per liter. What best describes this solution?
Acidic with a pH of 3
A solution with a pH of 6 has how many more hydrogen ions (H+) in it than a solution with a pH of 7?
10 times
the chemical equation for the formation of Hydronium and Hydroxide ions in pure water can be simplified to represent the dissociation of water. What is the correct equation for the dissociation of water?
H2O —> OH- + H+
One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when places in an aqueous solution, dissociates into bicarbonate ion (HCO3-) and a hydrogen ion (H+).
If the pH of blood increases, one would expect_______.
A decrees in the concentration of H2CO3 and an increase in the concentration of H+
The results from Stanley Miller’s 1953 experiments can best be used to support what hypothesis?
Organic molecules can be synthesized abiotically under conditions that may have existed on early Earth.
Why are hydrocarbons insoluble in water?
The majority of their bonds are non polar covalent carbon-to-hydrogen bonds.
Increasing amounts of the greenhouse gas CO2 are produced as a result of the combustion of fossil fuels. About 25% of the human generated CO2 becomes dissolved in the ocean. What is the effect of the pH of the ocean resulting from increased amounts of this gas?
The pH is decreased
Carbon can form up to ______ bonds with other atoms making it a very versatile atom. This is a major reason why life is based on this element.
4
hydrophobic substances such as vegetable oil are…
non polar molecules that repel water molecules
Which of the following molecules has the fewest characteristics of an organic molecule?
Methane, Keratin, Water, Hemoglobin, or Cellulose?
WATER!!!!
Thalidomide is a medication for the treatment of nausea and was used extensively in the 1950s and 1960s by expecting mothers. The birth defects that were related to use of the medication was due to what property of this drug?
The form of the drug responsible for birth defects is an enantiomer
Glucose and Fructose both have the molecular formula C6H12O6. Glucose and Fructose are…
Structural isomers
What is true of carbon?
It can form both polar and non polar bonds
In order for a molecule to be an enantiomer, there must be an asymmetric carbon atom. What is an asymmetric carbon?
The carbon atom has formed covalent bonds with four different chemical groups
A functional group that cells use as a source of energy that can drive biological reactions is…
a phosphate group
Emergent properties…
result from the interactions of parts within a system.
Ex.) the interactions between the population and environment in an ecosystem; Organisms adapting and evolving to suit their environments.
One unique property resulting from the structure of water molecules is that ice floats on water. Why is this important?
Solid water is less dense than liquid water, it insulates the water below it as it floats, allowing moron life to flourish. If ice was more dense, life would freeze and die in the ocean.
What functional groups are found in the building blocks of proteins?
Hydroxyl, carboxyl, amino, sulfhydryl, carboxyl, and methyl
What class of biological molecules are NOT polymers?
lipids
TRUE or FALSE
The primary structure of a protein determines its 3-D shape or conformation
true
Proteins are macromolecules made up of subunits called _______ and bound together by covalent _______ bonds.
amino acids, peptide
A single nucleotide in DNA or RNA consists of what?
A nitrogenous base, a phosphate group, and a 5 carbon sugar
Proteins perform what function in cells?
Enzymes, transport, hormones, structural.
Interactions between the _________ of a polypeptide are primarily responsible for the formation of a protein’s tertiary structure.
side chains
When nucleotides are joined to form a polynucleotide strand _________.
A covalent bond forms between the sugar of one nucleotide and the phosphate of a second
What best summarizes the differences between DNA and RNA?
RNA contains the base uracil, whereas DNA contain the base thymine
The double helical structure of DNA consists of two polynucleotide strands that are held together by ________ bonds between paired ________.
hydrogen, bases
Biological molecules that have the general formation of CH2O are:
Carbohydrates
TRUE or FALSE
The enzymes in animals and humans that digest polysaccharides can break down glycogen, starch, and cellulose
False
In polysaccharides, the monosaccharide subunits are connected by what type of covalent bond?
glycosidic bond
Carbohydrates perform what functions in cells?
Storage of energy
What property is shared by all lipids?
They are hydrophobic
What is true of both starch and glycogen?
They are long chains of glucose molecules connected together.
Saturated fats…
Contain only carbon-hydrogen single covalent bonds
How do phospholipids interact with water molecules?
the polar heads interact with water; the non polar tails do not
What structure is common to plant and animal cells?
Mitochondrion
Cell size is limited by…
The ratio of the surface area to volume
A cell with an extensive area of smooth endoplasmic reticulum would be expected to…
synthesize large quantities of lipids
What is common to both prokaryotic and eukaryotic cells?
ribosomes
Collection, packaging, and sorting of molecules synthesized in the cell is a function of the…
Golgi apparatus
Tay-Sachs disease is a human genetic disease that results in cells that are unable to break down (digest) a specific type of lipid. Which cellular organelle must be involved in this condition?
The lysosome
The membrane of the endoplasmic reticulum is continuous (directly connected to) what?
the Nuclear Envelope
Where are ribosomes found in the cell?
In the cytoplasm and on the rough endoplasmic reticulum
The function of a ribosome is to…
Synthesize proteins
the endomembrane system does NOT include…
Cytoskeleton
What is the function of chloroplasts?
The site of photosynthesis in plant cells
What is a function of the cytoskeleton?
Movement of the entire cell, movement of material inside the cell, and provides support for the cell
Energy transformation reactions are carried out in which of the organelles?
The chloroplast and the mitochondria
The evolution of eukaryotic cells most likely involved…
Endosymbiosis of a small prokaryote by a larger cell which evolved into mitochondria
Cillia and flagella are appendages that are used for cellular locomotion (movement). These structures are composed of which type of cytoskeletal protein?
Microtubules
How are chloroplasts and mitochondria different from other organelles in the cell?
They contain their own ribosomes and DNA
The term amphipathic refers to the ability of some molecules to
interact with both water and non polar substances
What is true about the movement of membrane phospholipids?
They can drift and exchange places with other phospholipids on the same face of the membrane
What kinds of molecules pass directly through a cell membrane most easily?
Small and hydrophobic
The current theory (model) of the membrane structure is called the…
fluid mosaic model
What is a correct description of the process of diffusion?
It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration
Cholesterol is an essential component to most eukaryotic cell membranes. Why is cholesterol important for membrane fluidity
It restrains the fatty acid chains of phospholipids as the temperature increases and it prevents the tight packing of fatty acids at lower temperatures.
If you put a red blood cell in 0.1 M solute solution, it will shrink as the water moves out. This is because the 0.1 M solute solution is…
Hypertonic
What is true of osmosis?
In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration
If a single celled organism is put into a freshwater lake containing lower concentrations of solute compared to the inside of the cell, what will happen?
It will swell as water moves in
“If a single celled organism is put into a freshwater lake containing lower concentrations of solute compared to the inside of the cell, what will happen?”
The tonicity of the freshwater lake is…
hypotonic
What is true about the process of active transport?
Moves molecules against a concentration gradient, requires energy, and uses membrane proteins to transport molecules
How is the information contained in the sequence of nucleotide bases related to the overall shape of a protein molecule?
The sequence of nucleotide bases is used to determine the sequence of amino acids in proteins. The specific sequence of amino acids (the primary structure) determines the protein’s shape, which then determines the protein’s function.
The fluidity of a membrane can be changed by several different factors including temperature and phospholipid composition. Explain how the fluidity of a membrane is affected by these tow important factors
The temperature can affect the fluidity of the membrane in that lower temps typically decrease fluidity while higher temps typically increase fluidity. Additionally, the presence of either saturated or unsaturated fatty acids in the phospholipid composition can affect fluidity.
Saturated fatty acids contain no double bonds and have the ability to pack together tightly while the double bonds in unsaturated fatty acids have a “bent” shape, preventing packing. Cholesterol, a third factor, acts as a buffer to prevent the membrane from becoming too fluid or too solid.
What is the membrane potential of a cell?
The separation of charges or voltage across the plasma membrane
How is the membrane potential of a cell generated?
By the active transport of positively charged ions to the extracellular side
What is an example of potential energy rather than kinetic energy?
A molecule of ATP before it is hydrolyzed
What term describes the cellular process of breaking down large molecules into smaller ones?
Catabolism
Entropy…
Represents heat given off from a reaction, will always increase for a spontaneous reaction, and represents disorder
What is an example of an anabolic reaction?
The synthesis of a carbohydrate molecule during photosynthesis
What is true for all exergonic reactions?
The products have less total energy than the reactants
Why is ATP an important molecule in metabolism?
The energy released during ATP hydrolysis can be coupled to a reaction that is endergonic
For the hydrolysis of ATP, what is true?
ATP + H2O —> ADP + Pi
ATP has a larger amount of free energy than the products ADP and Pi.
A reaction that results in products with a lower amount of free energy can be described as…
spontaneous and exergonic
The molecule or molecules that are acted on by an enzyme are called?
substrates
What is true about enzymes?
Enzymes increase the rate of a reaction, they are very specific for the substrates that they interact with, and they do not change the free energy of the reactants or products during a chemical reaction.
The active site of an enzyme is the region that…
interacts with the substrate
Enzymes speed up chemical reactions by lowering the ___________ of the reaction.
activation energy
A molecule that binds to the active site of an enzyme and prevents the substrate from binding is called a …
competitive inhibitor
The normal regulation of enzymes in metabolic pathways involves the activation or inactivation of the enzyme by other molecules that bind to the enzyme at a region that is different than the active site. This process is called…
Allosteric regulation
What are the stages in cellular respiration?
Glycolysis, The Citric acid cycle, and oxidative phosphorylation
When a molecule of NADH loses an electron, the molecule becomes…
Oxidized
What correctly describes the reaction?
C6H12O6 + 6O2 –> 6CO2 + 6H2O + ATP
Glucose is oxidized and Oxygen is reduced
What product is NOT an overall product of Glycolysis?
water
What is the energy investment phase in Glycolysis?
ATP molecules are used to split a molecule of glucose
Where does Glycolysis occur in the cell?
Cytoplasm
The Citric Acid Cycle does what?
Produce NADH, oxidize the rest of the glucose molecule, and produce ATP
The CO2 produced during cellular respiration is generated in…
The citric acid cycle
The reactions of the citric acid cycle occur in the ________ of the mitochondria
matrix
The final acceptor of electrons in the electron transport chain is…
O2
What happens during the electron transport chain as electrons are passed from one carrier to another?
Hydrogen ions are pumped across the inner membrane of the mitochondria
Which step in cellular respiration produces the most ATP
oxidative phosphorylation
What sequence describes the path by which ELECTRONS move from high-energy to lower-energy molecules in aerobic respiration?
glucose > NADH > electron transport chain > oxygen
The electron transport chain of cellular respiration is located in which part of the mitochondrion?
Inner mitochondrial membrane
What is the source of energy that is driving the production of ATP during oxidative phosphorylation?
The movement of hydrogen ions across the inner mitochondrial membrane
When oxygen levels are low, cells can produce ATP only from glycolysis by fermentation. What is the key step in fermentation that allows cells to continuously synthesize ATP from glycolysis?
the regeneration of NAD+ by oxidizing the NADH produced by Glycolysis.
TRUE or FALSE
In the process of cellular respiration, only carbohydrate molecules are able to be used to produce all of the necessary ATP required by a cell.
FALSE
Where do the light reactions of photosynthesis occur?
In the thylakoid membrane
What are the differences between autotrophs and heterotrophs?
Autotrophs, but not heterotrophs, can produce their own food from CO2 and sunlight
In photosynthesis, a molecule of _______ is oxidized and a molecule of ________ is reduced.
6CO2 + 6H2O + Sunlight –> C6H12O6 + 6O2
H2O, CO2
Which photosystem in photosynthesis is responsible for the production of ATP?
Photosystem II
What sequence correctly represents the flow of electrons during photosynthesis?
H2O > NADPH > Calvin Cycle
What step in photosynthesis is responsible for the splitting of a molecule of water and the production of O2 gas?
Photosystem II
What pair of molecules required for the Calvin cycle are produced during the light reaction of photosynthesis?
ATP and NADPH
In the cells of the leaf of a plants, synthesis of ATP by the chemiosmotic mechanism occurs during…
Photosynthesis and cell respiration
The enzyme Rubisco functions in the Calvin cycle and is estimated to be the most abundant protein on Earth. Why is the function of Rubisco so important for life on Earth?
It functions to fix carbon atoms from CO2 gas to produce organic molecules
Cellular respiration in mitochondria and photosynthesis in chloroplasts are the most important processes in cells involving the transformation of energy. In relation to energy transformation and metabolism, describe one example each of how photosynthesis and cellular respiration are similar and how they are different.
Photosynthesis and cellular respiration are similar in that they are both redox(oxidation and reduction) reactions. In photosynthesis, carbon dioxide is reduced and water is oxidized while in cellular respiration, glucose is oxidized and oxygen is reduced.
These processes differ in that photosynthesis is an anabolic reaction and cellular respiration is a catabolic reaction. Photosynthesis builds complex molecules, requiring energy, while cellular respiration breaks down glucose, releasing energy
What is an enzyme and why are they essential for life?
An enzyme is a protein that speeds up a specific chemical reaction. They are vital in the regulation of metabolic processes, making it so that organisms are able to function. If an enzyme is unable to function in a cell, the process it speeds up would not occur fast enough when needed, resulting in a lack of necessary molecules.
What does not take place during interphase of the cell?
M Phase
The somatic or body cells of animals typically have _______ set(s) of chromosomes and are considered ______.
Two, diploid
In humans and most animals, the somatic cells derived from a single celled zygote divide by which process?
mitosis
what are sister chromatids?
Identical DNA molecules that result from the copying of DNA in the cell
The chromosomes are arranged at the center of the cell
Metaphase
The nuclear envelope begins to break apart
prometaphase
chromosomes begin to condense becoming more compact
prophase
The chromosomes of the two daughter nuclei become less condensed and the mitotic spindle disassembles
Telophase/cytokinesis
The sister chromatids separate from one another and move to opposite sides of the cell
Anaphase
What is true for the somatic cells of a species that contain 20 chromosomes in their sex cells (gametes)
The haploid cells will have 40 chromosomes
Every gene has a specific locus. What does the term locus refer to?
The specific region of the chromosome where the gene is found
What is the name of the structure made of proteins on a chromosome that connects to the microtubules of the mitotic spindle?
kinetochore
The correct sequence of steps in Mitosis is…
prophase, pro metaphase, metaphase, anaphase, telophase/cytokinesis
What molecule is synthesized at specific times during the cell cycle and forms an active complex with kinase?
cyclin
The M checkpoint occurring during cell division functions to insure that…
The chromosomes are attached to spindle microtubules and are arranged at the center of the cell.
A cell can only pass through the ______ checkpoint if DNA replication has been completed
G2
What is true concerning cancer cells?
Cancer cells divide continuously and are not blocked by the cell cycle checkpoints
What happens during the process of synapsis?
Homologous chromosomes come together and pair
What is true of the process of meiosis?
Four genetically unique haploid cells are produced
Crossing over occurs between what?
Non-sister chromatids of homologous chromosomes
the purpose of meiosis is…
to reduce the number of chromosomes in daughter cells to half of those of parent cells
If there are 36 chromatids in a cell at metaphase of meiosis I, how many CHROMOSOMES are there in each daughter cell at the end of meiosis II?
9 chromosomes
After telophase I of meiosis, the chromosomal makeup of each daughter cell is…
Haploid and the chromosomes are composed of two chromatids
Pairs of homologous chromosomes are aligned at the center of the cell
metaphase I
Crossing over occurs
Prophase I
Sister chromatids separate
anaphase II
The homologous chromosome pairs separate
Anaphase I
For Mendel’s monohybrid cross experiments with the pea plant, two true-breeding (homozygous) parents with different traits are __________ to produce the F1 offspring
cross-pollinated
What is the difference between a monohybrid and a dihybrid cross?
A monohybrid cross involved parents that differ for a single character while a dihybrid cross involves parents that differ in two characters.
Mendel’s law of segregation states that…
the two alleles for a given characteristic separate into different gametes.
Independent assortment of chromosomes in meiosis is a result of…
The random way in which each pari of homologous chromosomes line up in metaphase I during meiosis
How many different gametes could be produced through independent assortment by an individual with the genotype YyRr
4
What are alleles?
alternative versions of a gene
____________ occurs when both alleles contribute to the phenotype in a heterozygote
codominance
You are studying the inheritance of flower color in a species that exhibits red and white colored flowers. After crossing two true-breeding red and white flower plants, the phenotype of the F1 plants are pink. What is this an example of?
Incomplete dominance
A woman who has type O blood has twin children that also have type O blood. What is the possible genotype of the biological father?
The father could be A, B, or O
Huntington’s disease is caused by a dominant allele. One parent has the disease, and the other parent is normal and the couple has had one normal child. What is the probability that their 2nd child will have Huntington’s disease?
50%
Multifactorial diseases such as heart disease or diabetes…
Can be caused by different reasons, including both genetic and environmental
The concept of independent assortment is relevant to Mendel’s dihybrid cross experiments with 2 different genes as well as the behavior of chromosomes in meiosis. Explain how Mendel’s concept of independent assortment is consistent with the process of meiosis.
Mendel developed the Law of Independent Assortment from the results of dihybrid crosses. The law can be states as follows: two or more genes assort independently. Each pair of alleles segregates independently of the other pair of alleles. Genes, specifically the alleles of genes, are on chromosomes. Mendel’s observations are consistent with meiosis because the random orientation of homologous pairs in Metaphase I explains how the alleles of different genes can be assorted into all of the possible arrangements of alleles in the haploid gametes. For an individual heterozygous for two genes, results in a characteristic ration of phenotypes for their offspring (9 Dom both : 3 Dom A, rec B : 3 rec A, Dom B : 1 rec both).
Genetic variation in higher eukaryotic organisms such as plants and animals is increased in meiosis during the formation of gametes. Explain one way in which new combination of alleles of genes are generated in meiosis.
Crossing over in meiosis is the process in which non-sister chromatids “cross over” and exchange sections, resulting in differing combinations of alleles of genes.
