Bell ringers 3/20/18- 3/26/18
In the drawing, the gene is located at a specific site on a(n) ______ strand.
DNA
The molecular sequence, or blueprint for a protein, is originally carried by which molecule?
DNA
If a cell starts with 48 chromosomes, then each new cell, or gamete, produced at the end of the process will contain ________ chromosomes.
24
Place the components in order, from smallest to largest.
B-C-D-A
The following diagram demonstrates the flow of water when a cell is placed in different aqueous solutions. Review the labels at the top of each picture. If a marine plant is placed in a salt water aquarium, predict the flow of water and salt into/out of the plant's cells.
Because the solution is isotonic, there will be no net movement of either water or salt.
Chromosomes, which contain DNA, have several functions. All BUT ONE of these statements is a function of chromosomes.
Chromosomes help an organism produce usable energy.
DNA, amino acids, and proteins are all molecules that play a vital role in your life, even though you have never seen them. In fact, these three types of molecules are tightly linked. What is the relationship between them?
DNA codes call for specific amino acids, which are assembled into proteins needed by your body.
Most dietary and storage lipids are triglycerides. This means that they are made of glycerol combined with three carboxylic acids, called fatty acids. Identify the lipid by its formula.
Image B is the lipid. Note the three fatty acids joined the glycerol backbone.
The role of enzymes in biological systems is to catalyze chemical reactions. In 1894, chemist Emil Fischer proposed the lock and key analogy of enzyme action. This analogy explains the specific action of an enzyme with a single substrate. Compare the two models seen here. How do they BOTH represent the lock and key analogy?
Only a specific substrate fits into the active site of the enzyme.
The human stomach secretes an enzyme known as pepsin. This enzyme breaks down proteins into smaller chemical molecules called peptides. If pepsin was mixed in a laboratory with sugar molecules like glucose, what is the MOST LIKELY result?
Pepsin will probably NOT react with the sugar glucose since it is an enzyme that breaks down proteins.
If the chemical enzyme pepsin was mixed with some proteins in a test tube in a laboratory, which of these outcomes would you predict?
Pepsin would probably NOT break down proteins in the test tube because pepsin is designed to work at very acidic pH ranges.
DNA encodes the information necessary to produce the proteins needed by your body. To make these proteins, DNA first undergoes a process known as transcription. This is when the information on a DNA strand is transferred to a molecule very similar to DNA, known as _______ .
RNA
The codon chart shown here uses the three base sequence found on the mRNA molecule after the information is copied from DNA during transcription. If the mRNA message is AAC UAC UGC, what was the original DNA base sequence?
TTG ATG ACG
Compare the food energy in calories from burning the chip and the saltine. How can you explain this differences in terms of chemical composition?
The chip contains more lipids than the saltine.
In an experiment, a student mixed a substrate and an enzyme. Which statement BEST explains the reaction?
The enzyme and the substrate form an enzyme-substrate complex.
Pepsin, a common enzyme found in the stomach, is most active at pH values between 0.5 and 2.5. It works slowly between pH values of 2.6 and 3.4. Beyond a pH of about 3.5, it becomes completely inactive. Why does this happen?
The protein chain in the enzyme is denatured, permanently inactivating it as the pH approaches 7.
Imagine the pH of the environment in which the hydrolysis of sucrose is to occur has dropped to 2. How will this drop in pH influence point D in the model?
The substrate (A) will no longer fit into the active site (C) because the enzyme has changed shape.
How would a saltwater fish respond if it is put in an aquarium of fresh water?
Water would move into the cells of the fish
In an experiment to study the effect of proteases on proteins, what is the MOST LIKELY effect of a major change in pH?
a change in shape of the active sites of the enzyme
Translation of the DNA sequence AAGCTGGGA would result in
a sequence of three amino acids linked by peptide bonds.
Living cells use ____________ as their main source of energy
carbohydrates
Most biological macromolecules contains carbon, hydrogen and oxygen atoms. Which of these has the carbon, hydrogen and oxygen in a 1:2:1 ratio?
carbohydrates
No matter what the cell type, prokaryotic or eukaryotic, plant or animal, the ____________ forms a protective barrier between the exterior environment and the interior of the cell.
cell membrane
DNA is typically found in cells in the form of a very long strand that is coiled many times and contains thousands or millions of nitrogen bases. Which term best describes this very long molecule of DNA?
chromosome
Inherited traits are passed down from our parents to us, their offspring, by the information that is coded in our parents'
chromosomes
Your eye color, sex, and hair color are all determined by the DNA in your genes. Where are these genes located?
chromosomes
On a strand of the mRNA the bases are read in groups of three. What is the correct term for a group of three bases on the strand of mRNA?
codon
Which type of RNA is NOT involved in the translation process shown in the image?
endoplasmic
Cells are able to remove large amounts of material using
exocytosis.
This section of the cell membrane illustrates one method of cellular transport. Consider steps A, B, and C. What transport mechanism is represented by the model?
facilitated diffusion
Brown eyes in humans is a dominant trait. We inherit dominant traits from our parents, some from our mother and some from our father, in the form of
genes
Curly hair, large nose, brown eyes: our __________ give the instructions that determine human traits, like these.
genes
All BUT one of the girl's traits are determined by her chromosomes. That is
how long her hair is
The chart matches messenger RNA codons with amino acids. A DNA strand has the codon AAT. According to the chart, the corresponding messenger RNA codes for which amino acid?
leucine
A wide range of molecular compounds dissolve in water. This allows water to act as a medium for moving molecules into and out of cells and tissues. All BUT ONE of these compounds dissolve in water. They are
lipids
It is advantageous for animals that migrate to store energy in the form of lipids rather than carbohydrates. This is because
lipids weigh less and store more energy than carbohydrates.
All of these are methods by which a cell
maintains homeostasis.
Substances that enter the cell without the expense of cellular ATP, but are too large to directly pass through the membrane, use ________________________ in order to gain access to the inside of the cell.
membrane proteins
Gases such as oxygen and carbon dioxide cross the plasma membrane by
passive diffusion through the lipid bilayer.
Enzymes are both pH and temperature specific. Seen here are the reaction rates of three common digestive enzymes. Based on the data, which enzyme(s) require(s) the addition of HCl for optimum activity?
pepsin
The graph illustrates the activity level of three common digestive enzymes, across a range of pH values. Which enzyme is likely to be the most active in the acidic environment of the stomach?
pepsin
In humans, excess blood glucose is stored in the liver and in muscle tissue in the form of glycogen. Glycogen is a long chain of glucose molecules bonded together. Because of this, glycogen is called a _____________________.
polysaccharide
All the biological macromolecules contain Carbon, hydrogen and oxygen. However, most do not contain nitrogen. The category that contains nitrogen are
proteins
The central dogma of molecular biology is centered upon the process of protein synthesis, in which the information from DNA is transcribed and translated, resulting in multiple amino acids being joined to form _______________.
proteins
The sodium-potassium pump functions to pump
sodium ions out of the cell and potassium ions into the cell.
Consider the activity and specificity of the three enzymes. Pepsin is most active in the human ________ and helps to digest __________.
stomach;protein
The diagram represents the ____________ formula of glucose.
structural
Messenger RNA carries a(n) ___________ of the DNA's instructions out of the nucleus to the ___________.
transcript; ribosome
During _____________, the cell uses information from messenger RNA to produce proteins.
translation
The picture shows an experimental set up for the process of osmosis. The potato has a cavity on top, as shown in the picture. Some sugar solution is poured into the cavity and the potato is placed in a beaker of water. After some time, it is observed that there is a rise in the level of liquid in the cavity. This confirms that
water from the beaker has moved into the cavity.