Biology Exam 2
Transcription
(genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA
During meiosis, haploid gametes (egg and sperm) are made. How many alleles for one gene can one gamete have?
1
how does meiosis and sexual reproduction lead to genetic variation in offspring?
1. Independent assortment 2. Random fertilization 3. Crossing over
When do we need new cells?
1. replace/ repair 2. growth 3.development 4. reproduction
For most genes, people have ______ alleles for each gene
2
A ______is a lump of abnormal cells that, although growing out of control, remains at its original site.
benign tumor
Mitosis
cell division in which the nucleus divides into nuclei containing the same number of chromosomes, the chromosomes line up and the sister chromatids are pulled apart into two identical daughter cells.
bottle neck effect (genetic drift)
change in allele frequency following a drastic reduction in population size; many endangered species display this
What happens during interphase before a cell can begin to divide?
chromosomes are duplicated
Humans have 23 types of chromosomes (Autosomal 1-22 and the sex chromosomes). In most cells, humans have 2 sets of these chromosomes (46 total). When a cell has 2 copies of each chromosome it is called:
diploid
Cytokinesis
division of the cytoplasm to form two separate daughter cells
After DNA replication, __________.
each of the two daughter DNA molecules contains one strand from the original DNA molecule and one newly synthesized strand
Drag the labels to the appropriate locations on this flow chart.
gather plasmid and target DNA --->cut DNA with restriction enzymes------>create a recombinant plasmid----->create transgenic cells----->harvest product
A section of DNA in a chromosome that encodes for a single protein is called a _________.
gene
Gene flow
genes shared between populations
A(n)_________ is a protein that promotes cell division. In excess, such a protein may lead to cancer.
growth factor
Artificial selection
humans determine breeding pairs and what traits are selected
Macroevolution
large-scale evolutionary changes that take place over long periods of time
Transcription is the production of ______ from DNA and occurs in the _______
mRNA/nucleus
Translation begins when a __________ molecule binds to a __________.
mRNA; small ribosomal subunit
A ________ is an abnormally growing mass of cells that is actively spreading through the body.
malignant tumor
DNA nucleotide structure
nitrogenous base, sugar deoxyribose, and phosphate group
branching and nonbranching evolution
nonbranch - an ancestral population changes gradually branching - an ancestral population splits into two or more populations
A researcher has identified a mutation in a gene for a protein that is usually 636 amino acids long. The protein product of the mutated gene is only 20 amino acids long. This mutation is probably a __________.
nonsense mutation
What are the monomers that make up DNA and RNA?
nucleotides
founder effect (genetic drift)
occurs when a few individuals become isolated from a larger population
A gene that causes a cell to become cancerous is called a(n)
oncogene
What is a sister chromatid?
one half of a duplicated chromosome
gene expression
process by which a gene produces its product and the product carries out its function
A normal gene that, if mutated, can lead to cancer is called a(n)
proto-oncogene
Variations
result of different alleles, or different versions of a gene
Heritability and Evolution
Living organisms acquire characteristics during their lifetimes, but such characteristics are not heritable so they are lost when the individual dies
the spread of cancer cells from their site of origin to other sites in the body.
Metastasis
During transcription of a specific gene, which of the following serves as a template for the formation of RNA?
One strand of DNA
What is a sex-linked gene and how does this affect inheritance when compared to genes on autosomal(not an X or a Y) chromosomes?
One that is carried on an X chromosome; X-linking also determines expression. Among males, almost all genes on the X chromosome, whether the trait is dominant or recessive, are expressed because there is no paired gene to offset their expression.
Natural selection
Organisms with certain traits are more likely to survive and reproduce than other organisms
What is the BEST definition for Natural Selection?
Organisms with certain traits are more likely to survive and reproduce than other organisms
RNA nucleotide structure
Phosphate group; Sugar (ribose); Nitrogenous base (a-u g-c)
Translation
Process by which mRNA is decoded and a protein is produced
Translation is the production of _____ from mRNA and occurs in the ________ or the Endoplasmic Reticulum.
Protein/cytoplasm
How are new alleles introduced into a population?
Random mutations
what causes genetic variation in a population?
Random mutations sexual reproduction
Which of the following mutations is LEAST likely to result in harmful changes to cellular proteins?
Silent mutation
population
a group of individuals of the same species living in the same place at the same time and can interbreed.
What is a codon?
a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.
What is a chromosome?
a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
Which of the following is FALSE?
a) The sugar part of the nucleotides are different between RNA and DNA b) RNA is single-stranded, DNA is double-stranded c) DNA uses the nucleotide Uracil (U), RNA uses Thymine (T) d) A codon is three nucleotides of mRNA that code for one amino acid Answer C DNA uses the nucleotide Uracil, RNA uses Thymine
Inheritance - ReviewIf you change the sequence of nucleotides in a gene, what mighthappen to the protein?
a. Nothing b. Change the amino acid sequence of the protein c. Change the shape of the protein d. Change the function of the protein e. All of the above are possible answer: e all of the above
THE CAT ATE THE RAT (change one letter R to H) This mutation is an example of a? This mutation will result in?
a.point mutation b.a sentence with a different meaning
(Delete letter C) This mutation is an example of a? This mutation will result in?
a.point mutation c.a non-functional sentence(no real words)
Gene pool
all the forms of all the genes in a population
Sexual selection
alleles that confer a sexual advantage will increase in a population
adaptation
an accumulation of modifications that help a species survive
genetically modified organism (GMO)
an organism produced by copying genes from a species with a desirable trait and inserting them into another species
(Add a letter B in the sixth letter place) This mutation is an example of a? This mutation will result in?
b.frameshift mutation c.a non-functional sentence(no real words)
base pairing rules
rule that describes how nucleotides form bonds in DNA; adenine (A) always bonds with thymine (T), and guanine (G) always bonds with cytosine (C)
Why is it important that gametes are haploid and not diploid?
so that every generation of offspring doesn't have twice the number of chromosomes as their parents
Which of the following could you be certain is NOT a GMO at the grocery store?
steak
Genome
the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes
limited resources
the condition of there not being enough resources to fulfill all wants and needs
Speciation
the formation of new and distinct species in the course of evolution.
A(n)_______ gene is a gene that encodes proteins that inhibit cell division. Such proteins normally help prevent cells from becoming cancerous.
tumor-suppressor gene
Meiosis
two rounds of cell division - first homologous pairs separate into two new cells, then sister chromatids separate - you are left with 4 unique daughter cells that are haploid
How many amino acids do our cells use to make proteins?
20
How many human cells are in the average human body?
38 trillion
How many chromosomes do most human cells have?
46 (23 pairs)
Genetic drift
A change in the allele frequency of a population as a result of chance events (random) rather than natural selection.
What is the BEST definition for microevolution?
A change in the gene pool, or the frequency of alleles, in a population over time
DNA
A complex molecule containing the genetic information that makes up the chromosomes. serves as the molecular basis for life
phylogenetic tree
A family tree that shows the evolutionary relationships thought to exist among groups of organisms
The c-src gene in animals is turned on during periods of cell growth and division. The Rous sarcoma virus genome contains a mutated form of this gene, v-src, which produces a protein that is always activated. Infections of chickens with this virus cause cancers to develop. What type of gene is c-src?
A proto-oncogene
Lipase is an enzyme (a type of protein) that breaks down fats. Which of the following statements about lipase are true? Select all that apply.
A specific sequence of bases in a DNA molecule codes for the lipase enzyme. The base sequence that codes for the lipase enzyme is duplicated during DNA replication.
Puberty is caused by the release of follicle stimulating hormone and luteinizing hormone from the pituitary gland. These hormones are delivered to the ovary in girls and initiate the monthly release of mature egg cells. This is an example of what mechanism of regulation of gene expression?
A typical signal transduction pathway
DNA is made up of 2 strands of nucleotides. These strands are kept together because the nitrogenous base of the nucleotides on one strand binds to the nitrogenous base of the nucleotides on the other strand. But the nucleotides can only pair up in a certain way (base pair rule). Which of the following is the correct pairing?
A-T and G-C
The theory of evolution
All living species have descended from common ancestor species, each new species having accumulated modifications that helped them survive in their habitat
What is the BEST definition for The Theory of Evolution?
All living things are descended from a common ancestor
Minor changes in the nucleotide sequence in a gene can lead to proteins that work a little different, and this can result in different traits. Different variations of the same gene in a population are called
Alleles
What is the BEST definition for Adaptation?
An accumulation of modifications that help a species survive
DNA is a double helix composed of nucleotides. Suppose that a portion of one of the two strands of a DNA molecule has the sequence GCAGTAG. What is the sequence of the opposite strand?
CGTCATC
. An individual with a malignant tumor is said to have
Cancer
What happens when there are too many bunnies and not enough resources - like carrots?
Competition
Replication
Copying process by which a cell duplicates its DNA
When new cells form what will they need to function?
DNA
How are DNA and RNA different?
DNA contains the bases A, G, C, and T; RNA contains the bases A, G, C, and U.
DNA is considered to be the molecule of life. Which two functions make DNA uniquely suited to this role?
DNA produces more of itself. DNA directs the production of proteins.
What accounts for different traits (diversity) within a population?
Different alleles
Which of the following is TRUE concerning benign tumors?
Do not spread to other parts of the body
What is the function of CRISPR-Cas9?
Edit a specific nucleotide sequence in living cells.
Microevolution
Evolutionary change below the species level; change in the allele frequencies in a population over generations.
How do we make an mRNA copy of DNA?
Follow the base-pair rules, but instead of "T" we will use a "U"
Most scientists describe biodiversity in terms of the number of species that have been discovered and described in scientific journals. Roughly 1.8 million species have been described, although most scientists think there could be as many as 50 million species or more currently living on Earth. However, in the video, Craig Venter seems more interested in the total number of discovered genes (he gives a total number of 20 million genes in the video) than the total number of discovered species. Why is that?
For recombinant DNA technology or for the creation of synthetic life, only the gene that produces a particular desired product is needed, and not the entire organism that carried the gene
If your cells are diploid, how could you reproduce without doubling the chromosome number in your offspring?
Gametes! they are haploid and contain only one copy of each chromosome
How would you describe the current status of gene therapy research?
Gene therapy has had limited success in a few cases. However, there is still a long way to go before gene therapy is deemed safe and effective enough for widespread use in curing genetic diseases.
A population of mice on island are about 50% brown and 50%black. A volcano explodes on an island and kills 90% of the mouse population. The surviving mouse population is now 80% brown, 20% black. What mechanism led to this evolution?
Genetic drift
The gene for the beta chain of normal human hemoglobin has the sequence CTC at the position for the seventh amino acid in the protein. A point mutation changing the sequence to CAC results in sickle cell hemoglobin. Use the genetic code to determine the change in the amino acid at position seven of the hemoglobin beta chain.
Glutamic acid to valine
What might happen if cells enter the mitotic phase when duplication is unnecessary? What might happen if cells in a tissue don't know when to stop duplicating?
Healthy cells only start dividing if there is a need for replication Unhealthy cells may undergo unregulated division cancer often begins when a cell divides and it shouldn't
Which set of the biologically related individuals would have identical numbers of STRs at all 13 locations?
Identical twins
What is the role of transcription factors?
Initiate gene expression
What makes a trait a benefit for survival and/or reproduction?
It depends on the environment
How did the first bacteria gain resistance to antibiotics ?
The bacteria inherited a random mutation from its parent bacteria.
There are four different nucleotides that make-up our DNA. Nucleotides have three parts, which part is different between different nucleotides?
The base
Which part of a nucleotide molecule in DNA encodes genetic information?
The base
Evolution
The change in frequency of traits of a population over several generations
Use the data table and your knowledge of cancer to identify which statements are true. Select all that apply.
The combined survivability of all types of cancer is about 65%. Reducing risk factors might decrease the number of cancer cases, but would be unlikely to decrease the cancer deadliness percentages.
genetic engineering
The direct manipulation of genes for practical purposes.
In viruses called retroviruses, the genetic information is contained in RNA; these viruses have no DNA. These viruses also have an enzyme called reverse transcriptase. What is its function?
The enzyme makes a DNA transcript of the viral RNA.
Overpopulation
The number of organsims in an area exceeds the capacity of the environment to support life at a decent standard of living.
What would happen to the population of bacteria if the person never took antibiotics?
The population would grow
Scientists like Craig Venter could choose to try to make any type of synthetic organism, from a bacterium to a mammal, but there are many things to consider when choosing a type of organism for research. Which of the following is a potential reason for choosing to create a type of organism other than a synthetic bacterium?
There is always a chance that a microscopic bacterium could escape undetected from the lab, and end up in the environment.
PCR is used to copy just a relatively small region of DNA, not the entire genome. How do researchers specifically target the region of interest?
They use two primers, each about 15 to 20 nucleotides long, that flank the region of interest.
Variability in Evolution
This increases the likelihood of evolution. It can be increased by mutations, immigration, sexual reproduction, and size. Natural selection, emigration ans smaller populations can lead to decreased variability.
What does it mean to be a carrier?
To be a carrier means that you are heterozygous for a recessive disorder.
In traditional recombinant DNA technology, a desirable gene from one organism is inserted into the DNA of a host organism. However, to create a synthetic life form, Craig Venter's team actually builds the entire DNA molecule from individual DNA nucleotides. Why would it be harder to create a synthetic life form than to use recombinant DNA technology?
To create a synthetic life form, you would need to understand the role of every gene, and make sure all of the genes were included that are necessary for the organism to survive.
Almost all of your cells have the same DNA in their nuclei
True
Similarities between human embryos, bird embryos, and reptile embryos suggest they all have common aquatic ancestors. True or False.
True
What is a homologous pair?
Two chromosomes of the same type, containing copies of the same genes laid out in the same order.
What happens during cytokinesis in animal cells?
Two daughter cells split apart
What would be an advantage to creating a synthetic organism, as compared to creating a genetically modified organism through recombinant DNA technology?
When creating a synthetic organism, you can more easily control the genes present in that organism, and make sure the organism cannot survive out in the environment.
A population of mice on island are about 50% brown and 50%black. There is no advantage to either color. A volcano explodes on an island and kills 90% of the mouse population. The surviving mouse population is now maintained at 80% brown,20% black. Is this evolution?
yes
Can an XY male inherit a genetic disorder if the gene is carried on the X chromosome?
yes
