Bio 101 - Exam 3

A diagram of the cell cycle is shown to the right. It maps the phases of the cell cycle and the checkpoints by which certain criteria must be met for the cell cycle to advance to the next phase. Select all the statements below that describe how a cell may respond at a checkpoint.

- Cell may find errors and delay cycle until they're corrected - Cell may exit cell cycle and enter non-dividing state - Cell may initiate next phase in cycle

Functions of miotic cell division?

- organism growth - cell regeneration - asexual reproduction

Genome

Collection of genetic material in a cell or organism

Function of chromosomes?

Compact DNA and facilitate proper distribution during cell division

What stimulates formation of red blood cells?

Erythropoietin

How do the nucleus and ribosomes work together to generate a protein?

In the nucleus, DNA is transcribed to mRNA, which the ribosomes use as instructions to synthesize a specific protein.

Earliest --> Latest

Interphase Prophase Prometaphase Metaphase Anaphase Telophase Cytokenesis

How are DNA fragments separated using gel electrophoresis?

Larger DNA fragments move more slowly through the gel than do smaller fragments.

transcrip vs translat

Transcription - occurs in nucleus - produces mRNA Translation - takes place in ribosomes - produces protein - involves tRNA

allele?

one variation of the code for a protein

region of DNA that recruits the transcriptional machinery

promoter

carries amino acid to ribosomes and binds to mRNA

tRNA

Why are some people more susceptible to cancer than others are?

- Tumor-suppressor genes (BRCA1 and BRCA2) normally function to inhibit tumor growth, but heritable mutations in genes increase likelihood for tumors to grow - Oncogenes are genes that increase likelihood of developing cancer, and when they are passed to offspring cancer is more likely to occur

A cell with mutated DNA may not be able to produce proteins accurately. What can lead to mutations in the DNA?

- Uncorrected DNA replication errors - Chemicals in tobacco smoke - UV radiation exposure

Which of the following are examples of genetically modified organisms (GMOs)?

- a farm-raised pig engineered to digest food more efficiently - a rice crop modified to contain more iron

Polymerase Chain Reaction (PCR)

1) Reaction of mixture contains three copies of particular DNA sequence 2) reaction mixture heated to 94C 3) double-strand DNA denatured to form single-strand DNA 4) temperature of mixture lowered to allow primers to anneal to DNA template 5) mixture heated to 72C 6) Taq polymerase synthesizes new DNA strand 7)Reaction mixture contains six copies of DNA sequence

Gene practice

12-22 HW 11

An organism has 28 pairs of chromosomes in its diploid somatic cells. How many chromosomes are in its gametes?

28 Somatic cells are referred to as body cells, and include all of the cells in the organism other than the reproductive cells. Gametes are the reproductive cells and include egg and sperm cells. The diploid cell described has 28 pairs of chromosomes, or 56 individual chromosomes. Gametes are haploid (n) cells, which have half as many chromosomes as a diploid (2n) cell. Because each pair was split in half during meiosis, the gametes should have only one chromosome from each pair remaining.

Meiosis

5 HW11

GMOs

Advantages - produce higher yield crops than traditional crops - pest-resistant plants reduce the amount of pesticides needed - drought-resistant plants allow crops to be - often have added vitamins to increase crop nutrition Disadvantages - gmo crops have an unknown impact on human health - pest-resistant plants may harm unintended organisms - cross pollination can transfer genes to traditional crops - generation and spread of resistant weeds

Mendel formulated the Law of Independent Assortment to explain the basic rules of inheritance based on his experiments with pea plants. With the modern understanding of chromosomes, alleles, and the process of gamete formation, what is the physical basis for the Law of Independent Assortment?

Alleles on nonhomologous chromosomes separate randomly into gametes during meiosis.

Some mutations do not affect the amino acid sequence of the protein produced using the mutated gene. How can the correct amino acid be incorporated into the protein despite a mutation in the gene sequence?

Amino acid specified by mutated codon may be unchanged by mutation

Amygdala vs Hippocampus

Amy - senses fear/anxiety inducing situations and begins body's response to them - directs memories of emotional situations into long-term memory Hippo - Moves info regarding places, events, and newly acquired facts into long term memory - Associates newly acquired factual info with info already stored in long-term memory

How does cocaine overstimulate postsynaptic neurons in brain's reward center?

Blocks reuptake of dopamine into pre-synaptic neurons

Respiratory System

Bronchi & Alveoli

Central Nervous System vs Peripheral Nervous System

CNS - consists of brain + spinal cord - processes info PNS - includes motor neurons - relays signals like motor output - can receive info directly from environment

Cancer vs Normal

Cancer - abnormal shaped nuclei - metastasize and spread - do not respond to internal cell signals Normal - differentiate into specialized cells - undergo apoptosis if genome damaged - adhere to neighboring cells within a tissue

Benign tumors are non-cancerous tumors. How are malignant tumors different from benign tumors?

Cells exhibit uncontrolled growth, ability to invade other tissues, & can metastasize

What are the structures in a cell that group genes together, are composed of chromatin (DNA and protein), and become visible under a light microscope during mitosis?

Chromosomes

LABEL DNA STRUCTURE

DNA Molecule --> Protein --> Chromatin --> Chromosome

What enzyme pairs corresponding nucleotides to preexisting DNA chain to synthesize new strand of DNA?

DNA polymerase

definition of recombinant DNA?

DNA that is composed of a combination of DNA nucleotides from two or more organisms.

Why does radiation therapy increase the risk of cancer reoccurring?

Exposure to radiation can damage the DNA of normal cells, which can contribute to cancer.

Checkpoints

G1: Cell resources and size assessed G2: DNA checked to be sure all chromosomes duplicated w/o damage M: All chromatids checked for proper attachment to spindle fibers

Phases of cell cycle

G1: cell prepares to replicate DNA S: DNA synthesized G2: sister chromatids presents M: mitosis occurs (See 2, 4, 5, 7 HW9)

Mutations

Germline - Inherited by offspring - Incorporated into all cells of offsprng - Occurs in reproductive cells Somatic - Nonheritable - found in a few body cells or tissues of an organism

Which blood component is responsible for carrying majority of oxygen found in blood?

Hemoglobin

CNS, Nerve Net, or None?

Human - CNS Comb jelly - Nerve net Sea anemone - Nerve net Sea sponge - No nervous system Butterfly - CNS

What intermolecular force holds two strands of DNA double helix together?

Hydrogen bond

Amino acid sequence

In nearly all organisms, the translation of mRNA to an amino acid sequence follows the universal genetic code shown in the codon table. Animal mitochondria and some microbes are exceptions. In most instances, mRNA sequences specify the amino acids show in the codon table. Codons are a sequence of three mRNA nucleotide bases that specifiy an amino acid.

mechanism by which new alleles are formed?

Mutations can occur in existing genes, which brings about new allele variations

Order of Tract

Nasal passages --> Pharynx --> Larynx --> Trachea --> Bronchi --> Bronchioles --> Alveoli

In the lungs, oxygen diffuses into the blood and is loaded onto hemoglobin for transport. In the tissues, oxygen is unloaded from hemoglobin and diffuses from the blood into nearby cells. What drives the diffusion of oxygen?

Partial pressure of oxygen

Why is it more difficult to catch your breath at higher altitudes?

Partial pressure of oxygen lower at higher altitudes, so there are fewer oxygen molecules available

What is the cerebellum?

Primarily regulates balance & motor control

Proto-oncogenes are genes that have the potential to become oncogenes through either mutation or an increase in expression. Classify the statements below as describing proto-oncogenes or tumor suppressor genes.

Proto-oncogenes - Genes code for proteins that normally promote cell division - Mutations that increase activity of these genes may lead to cancer Tumor suppressor genes - Genes code for proteins that normally prevent uncontrolled cell division - Mutations that decrease activity of these genes may lead to cancer - Some products of genes normally function in repairing damaged DNA

DNA/RNA SEQUENCE PRACTICE

QUESTION 10, 11, 14, 15, 16 HW8

protein complex that makes RNA polymers corresponding to a DNA template

RNA Polymerase

During the cell cycle, the cell must pass through several checkpoints that confirm that the cell is ready to progress to the next phase of the cycle. If the requirements of one phase have not been met, the cell cannot proceed to the next phase. These checkpoints help control the rate of cell division. If a mutation disables one of these checkpoints, what is most likely to happen?

The cell begins dividing too often, forming a tumor.

The respiratory system of most terrestrial arthropods consists of cuticle-lined ducts called _____, which open to the exterior by ____.

Tracheae; Spiracles

Zygote vs Gamete vs Fertilization

Zygote - diploid cell resulting from fertilization - fertilized egg cell Gamete - cell produced by meiosis - egg cell Fertilization - process fusing nuclei of two gametes

description of mRNA.

a linear sequence of ribonucleotides transcribed from DNA that carries instructions for protein production

What is Short Tandem Repeat (STR) analysis?

a procedure that compares the lengths of short, repeated DNA regions across samples

Which statement describes a gene?

a section of DNA in which the code for a protein is located

dominant allele

any allele that can hide the presence of a different allele

recessive allele

any allele whose presence can be masked by another allele

homologous chromosomes?

chromosomes with the same genes but different parental origin

examples of uses for genetically-modified organisms?

creating bacteria that produce bovine growth hormone to give to livestock creating bacteria that can produce insulin creating goats that produce spider silk for research

Which structure is part of the diencephalon?

hypothalamus

Diabetes is a cluster of metabolic disorders where individuals suffer from elevated blood sugar levels. To regulate their blood sugar, some diabetics must inject themselves daily with the hormone insulin, which reduces the amount of sugar in the bloodstream. Historically, therapeutic insulin has been produced by pigs and other animals. However, raising pigs and purifying their insulin for medical use is labor intensive and pig-derived insulin can produce immune reactions in some people. Based on the techniques of biotechnology, what would be the best alternative for producing therapeutic insulin?

insert the human insulin gene into the DNA of bacteria A common type of genetic modification involves taking a gene from one organism and inserting it into another organism. This allows the recipient organism to produce the protein encoded by the original gene. Genetic modification therefore goes beyond traditional selective breeding, which can only take advantage of traits that already occur in a species. In this situation, the use of pig insulin as a therapeutic for human diabetics came with several issues. First, it is expensive to raise pigs and extract their insulin. Second, some diabetics would have allergic reactions to pig-derived insulin. Rather than relying on an animal source of insulin, scientists used new biotechnology techniques to insert the human insulin gene into bacteria.

What causes normal cells to become cancer cells?

loss of cell cycle control

contains DNA in the cell

nucleus

crossing over?

occurs between homologous chromosomes increases genetic variation across gametes

Which of the following is an example of gene therapy?

replacing a disease-causing allele for a gene with a normal allele

organelle where proteins are constructed

ribosome

Function of mitotic spindle?

separating sister chromatids

genotype?

the pair of DNA sequences an organism has for a trait

phenotype?

the physical trait produced by an organism's genetic makeup

Cell division by mitosis is a mechanism of asexual cell replication. Some single-cell organisms reproduce by cell division, and cell division enables multicellular organisms to grow and to repair damaged cells. Which of the following are products of cell division by mitosis?

two daughter cells with identical chromosomes