DNA structure
What are the three components that make up a single DNA nucleotide?
1. Sugar - deoxyribose
2. Phosphate group
3. Nitrogen base
In the 'lock and key' model of enzyme action, what does the 'key' represent?
Substrate
The substrate is a specific molecule that fits into the enzyme's active site to undergo chemical change
What is the longest phase in cell cycle?
Interphase
How does the genotype (letters) of a recessive trait looks like?
Two lowercase letter
Which gas makes up most of Earth’s atmosphere but is "locked" in a form that plants and animals can't use directly?
Nitrogen Gas
According to the base-pairing rules (Chargaff's Rules), if a DNA sample contains 20% Adenine (A), what percentage of the sample will be Thymine (T)?
20%
Because Adenine always pairs with Thymine, their percentages in a double-stranded DNA molecule will always be equal.
What causes enzymes to become denatured (stop functioning)? Give the two main reason.
High temperature and abnormal pH
A cell spends the majority of its life in Interphase. During the S (synthesis) phase of Interphase, what critical process must occur before the cell can divide?
DNA Replication
In some flowers, crossing a red flower with a white flower produces pink offspring. What type of inheritance pattern does this represent?
Incomplete Dominance
During the stage of 'Assimilation,' how does nitrogen actually enter the body of a consumer, such as a rabbit?
B. The rabbit eats plants that have already incorporated nitrogen into their tissues.
What the difference between a nucleotide and a nitrogenous base? (show picture)
A nitrogenous base is just one component (the "letter" AT,CG), while a nucleotide is the complete package consisting of that base plus a sugar and a phosphate group.
Most enzymes in the human body work best at a pH of around 7. However, pepsin is an enzyme that breaks down proteins in the stomach. At which pH would pepsin likely show the highest activity?
A. pH 2
B. pH 7
C. pH 10
D. pH 14
A. pH 2
Stomach is highly acidic environment, and stomach enzymes like pepsin have evolved to function optimally at low pH levels.
When a baby is growing inside its mother, its hands first look like solid mittens. To make separate fingers, the cells in the "webbing" between the fingers are ordered to die and disappear.
What is the name of this "programmed" cell death?
Apoptosis
Write the genotype: In pea plants, green (G) is dominant to yellow (g). What are the genotypes for heterozygous green and homozygous yellow
Gg, gg
Imagine all the decomposers (like fungi and certain bacteria) suddenly disappeared from a forest. How would this break the nitrogen cycle?
A) Plants would start taking nitrogen directly from the air instead of the soil.
B) Nitrogen would get "locked away" inside dead plants and animals, so it couldn't get back into the soil for living plants to use.
C) The soil would get too much nitrogen because there would be nothing left to eat it.
D) Animals would stop producing waste, so the nitrogen cycle would speed up.
B) Nitrogen would get "locked away" inside dead plants and animals, so it couldn't get back into the soil for living plants to use.
What is the difference between mRNA and tRNA? (show picture)
mRNA provides the genetic code copied from the DNA, while tRNA serves as the transporter that delivers the correct amino acids to assemble the protein.
How do enzymes affect the activation energy required for a chemical reaction to occur?
Enzymes lower the activation energy required for a chemical reaction
If a mutation occurs during the S phase of the cell cycle, what would most likely the consequence?
DNA will be copied incorrectly leading to mutation
If two parents are heterozygous for a trait (A a X A a), what is the probability that their offspring will show the recessive phenotype?
25%
What happens to the nitrogen molecules in an animal's waste (urine) once it enters the soil?
D. Decomposers break it down and convert the nitrogen into ammonia.
In the cell, information flows from DNA to RNA to Protein. Use the DNA sequence below to complete the table and find the secret amino acid chain.
The DNA Code: T A C C C G A T T
The RNA Code: ____ ____ ____
Amino Acid: ____ ____ ____
The DNA Code: T A C C C G A T T
The RNA Code: A U G G G C U A A
Amino Acid: met gly stop
What happens to an enzyme after it has completed a chemical reaction and released the products?
Remains unchanged and can be reused for another reaction
Cancer is often described as a disease of the cell cycle. How does a normal cell become a cancer cell?
The cell ignores normal checkpoints and undergoes uncontrolled cell division.
In pea plants, tallness (T) is dominant over shortness (t). If a homozygous tall plant is crossed with a homozygous short plant, what will be the phenotype of all the offspring in the first generation?
100% - All Tall
How does human use of synthetic fertilizers often disrupt the local nitrogen cycle?
Excess nitrogen runoff to the water causing algal bloom and oxygen depletion for organism under water.