Biology: Test #3

What is the chromosome abnormality that causes Down syndrome?

A nondisjunction results in a person with an extra copy of chromosome 21.

How is the aging process linked to telomeres?

Cells with short telomeres can no longer divide, so damaged tissues cannot be repaired

Chromosomes contain most of the cell's ______ which acts as the molecule of heredity.

DNA

_____ is the self-replicating material present in nearly all living organisms; it is the main constituent of chromosomes and the carrier of genetic information.

DNA

_______ is a long linear polymer found in the nucleus of a cell, shaped like a double helix, and associated with the transmission of genetic information.

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 Extension

DNA polymerase runs until the end of the primer sequencing, completing the DNA replication process

denaturation

DNA strands heated to specified temperature to separate strands

When is cell-to-cell communication particularly important in regulating gene expression?

During embryonic development

Which genes are responsible for your overall structure, such as how many legs you have and where they develop?

Homeotic genes

What is the name of the syndrome that produces the XXY combination of sex chromosomes?

Klinefelter syndrome

Polymerace Chain Reaction (PCR)

Lab technique to create DNA copies used for paternity tests

What is gene regulation?

Mechanisms that turn on and off specific genes to change which proteins are made

How does a cell typically know when to divide?

Proto-oncogenes code for growth factor proteins that initiate cell division.

The principal role of _____ is to act as a messenger carrying instructions from DNA out of the nucleus for the synthesis of proteins.

RNA

_____ is used in all steps of protein synthesis and carries the genetic information of many viruses.

RNA

If DNA directs the production of RNA, what does RNA make?

RNA makes proteins

Which cells are most likely to have the gene for making telomerase switched on?

The cells in a developing embryo.

What must happen before a cell can begin mitosis?

The chromosomes must be duplicated.

What is different between two alleles of the same gene?

The information they carry. For example, one allele might carry the information for blue eye pigment, while the other carries the information for brown eye pigment.

Barr bodies are associated with ________.

X chromosome inactivation

What is a proto-oncogene?

a gene that codes for proteins that tell a cell when to divide

What is an oncogene?

a mutated proto-oncogene that causes a cell to divide uncontrollably

Your aunt specializes in oncogenes. What does she study? a) Genes that trigger cancer. b) Immunosuppressive genes. c) Genes that decrease a person's risk of getting cancer. d) Genes that cure cancer.

a) Genes that trigger cancer.

Which of the following processes generates a continuum (spectrum) of varying phenotypes? a) Polygenic inheritance b) Single-gene traits c) Epistasis d) Pleiotropy

a) Polygenic inheritance

Which of the following is NOT true about naked mole rats? a) Their cells do not produce telomerase. b) They can survive in burrows with high levels of carbon dioxide. c) They seem to be resistant to getting cancer. d) They often live for 30 years.

a) Their cells do not produce telomerase.

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) a proto-oncogene b) a mutated growth factor gene c) an oncogene d) a tumor suppressor gene

a) a proto-oncogene

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) a typical signal transduction pathway b) induction c) activation of micro RNAs d) homeotic genes

a) a typical signal transduction pathway

Which of the following is LEAST likely to be a health problem for someone with cystic fibrosis? a) obesity b) diabetes c) nutritional deficiencies d) frequent infections

a) obesity

Which of the following mutations is LEAST likely to result in harmful changes to cellular proteins? a) silent mutation b) missense mutation c) nonsense mutations d) frameshift mutations

a) silent mutation

Which part of a nucleotide molecule in DNA encodes genetic information? a) the base b) hydrogen bonds c) the sugar d) the sequence of phosphates and ribose molecules

a) the base

On what day does ovulation occur during the female reproductive cycle?

about day 14

Most human genes come in alternate versions called ________

alleles

Imagine that five hypothetical genes are arranged on a chromosome in the following order: G--H--I--J--K. Which two genes are most likely to have a crossover occur between them? a) A crossover is equally likely between each pair of genes. b) G and K c) G and H d) There is no way to know without further information.

b) G and K

Fur color in rabbits is controlled by multiple alleles. What does this mean? a) There are several genes that work together to determine a rabbit's fur color. b) Rabbit fur color is controlled by a single gene, but there are multiple versions of that gene. c) All of the rabbit coat color alleles are co-dominant. d) This is an example of pleiotropy.

b) Rabbit fur color is controlled by a single gene, but there are multiple versions of that gene.

If one polynucleutide strand of DNA has ACTTGACTAGCTA as its sequence of bases, what would be the sequence of bases on the opposite strand? a) ACTTGACTAGCTA b) TGAACTGATCGAT c) CAGGTCAGCTAGC d) GTCCAGTCGAGCG

b) TGAACTGATCGAT

The inheritance pattern for red-green color blindness is different for males compared to females. Red-green color blindness is much more common in males than in females. What does this suggest about the gene for red-green color blindness? a) This is an example of pleiotropy. b) The gene for this trait is located on the X chromosome. c) Males do not express this trait unless they inherit two copies of the red-green color blindness allele, while females express this trait even if they have inherited only one copy of the color blindness allele. d) The gene for this trait is located on the Y chromosome.

b) The gene for this trait is located on the X chromosome.

A series of three nucletodies that specifices an amino acid is a(n) __________. a) polymer b) codon c) residue d) DNA

b) codon

During cleavage, cell division is accompanied by a(n) ______________. a) increase in chromosome number per cell b) decrease in cell size c) decrease in chromosome number per cell d) increase in cell size

b) decrease in cell size

The allele that causes cystic fibrosis is recessive. An individual who is heterozygous for cystic fibrosis... a) cannot have children with cystic fibrosis. b) is a carrier. c) cannot reproduce. d) will have children who are all carriers of cystic fibrosis

b) is a carrier.

Which of the following biologically describes a hermaphrodite? a) Pistachio trees have female flowers on one plant, and male flowers on another plant. b) A human baby is born with XX chromosomes, but has a very large clitoris that resembles a penis. c) Earthworms can fertilize each other to produce offspring. d) A human baby is born with XY chromosomes, but lacks a penis and has a vagina.

c) Earthworms can fertilize each other to produce offspring.

Sickle-cell disease is a rare genetic disorder. Which of the following statements regarding the gene for sickle-cell disease must be true? a) Sickle-cell is a wild type trait and therefore must be dominant. b) Sickle-cell is a wild type trait, but we cannot say whether it is dominant or recessive. c) Sickle-cell is a mutant trait, but we cannot say whether it is dominant or recessive. d) Sickle-cell disease is a mutant trait and therefore must be recessive.

c) Sickle-cell is a mutant trait, but we cannot say whether it is dominant or recessive.

Which of the following is used to construct a molecule of DNA a) The sugar b) The base c) The phosphate group

c) The phosphate group

A DNA profile examines DNA from __________ a) a single location in the genome b) two locations in the genome c) multiple locations in the genome d) every site in the genome

c) multiple locations in the genome

A duplicated chromosome remains tightly paired with its partner at a region called the ________.

centromere

A __________ is an inherited feature that varies from individual to individual.

character

What is the most common STD that is caused by bacteria?

chlamydia

DNA and protein together form a complex called _________.

chromatin

________ are tightly coiled bundles of DNA and protein found in the nucleus of most living cells.

chromosomes

What are the 4 nitrogenous bases? Which pairs to which?

cytosine, guanine (always pair) thymine, adenine (always pair)

Which of the following processes does not generate genetic variation during sexual reproduction? a) Independent assortment b) Crossing over c) Random fertilization d) All of the processes above generate genetic variation

d) All of the processes above generate genetic variation

In a human, which of the following could be identified by the use of a karyotype? a) The adult hair color of an embryo b) Which X chromosome in a girl was inherited from her father c) Sickle-cell disease, a recessive mutation of the hemoglobin gene d) Klinefelter syndrome, where a male has two X and one Y chromosomes

d) Klinefelter syndrome, where a male has two X and one Y chromosomes

After DNA replication, __________. a) the original DNA molecule is destroyed b) a new daughter DNA molecule contains two newly synthesized strands that are identical copies of the original DNA molecule c) only one of the strands of the parent DNA molecule serves as a template for DNA replication d) each of the two daughter DNA molecules contains one strand from the original DNA molecule and one newly synthesized strand

d) each of the two daughter DNA molecules contains one strand from the original DNA molecule and one newly synthesized strand

Gel electrophoresis separates DNA fragments according to their ________. a) polarity b) base sequences c) charge d) length

d) length

Which of the following options lists the sequence of stages in embryonic development in the correct order? a) zygote, gastrula, blastocyst b) blastocyst, zygote, gastrula c) gastrula, blastocyst, zygote d) zygote, blastocyst, gastrula

d) zygote, blastocyst, gastrula

what is DNA?

deoxyribonucleic acid; double helix, forms in an anti-parallel structure made up of nucleotides

If an organism has two non-identical versions of a gene, the one that is expressed in the organism is called the _________ allele.

dominant

Central Dogma of Biology

explains the flow of DNA to RNA to Protein

TRUE or FALSE? Cells that are genetically identical will express the same level of each gene within its genome.

false

Meiosis starts with a single diploid cell and produces...

four haploid cells

_______________ involves the development and migration of the three tissue layers - ectoderm, mesoderm, and endoderm.

gastrulation

The __________ is the genetic makeup of an organism.

genotype

If a woman with curly hair and a man with straight hair have a child with wavy hair, the gene for this characteristic of hair shows __________.

incomplete dominance

Random orientation of homologous pairs of chromosomes during meiosis I results in alternative arrangements that contribute to genetic variation in offspring. This is called __________.

independent assortment

From which part of a developing embryo are stem cells derived?

inner cell mass

A cell preparing to undergo meiosis duplicates its chromosomes during ________

interphase

Human Genome Project

launched 1990 goal; locate and map all genes on human genome, locate detrimental genes linked to undesirable traits ethical issues; genetic discrimination, gene editing

Recessive disorders related to genes found on the X chromosome but not on the Y are more commonly expressed in ________.

males

genetic engineering

manipulation of genes for practical purposes typically includes production of recombinant DNA and recloning

biotechnology

manipulation of organisms of their components to make useful products

DNA technology

methods and applications for genetics in improving and understanding biological life

The ________ ________ is the two-layered membrane that encases the nucleus of a eukaryotic cell, separating the nucleus from the cytoplasm.

nuclear envelope

A protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm is called a ________ ______.

nuclear pore

The round body that sits inside the nucleus of a eukaryotic cell and makes ribosomal subunits from proteins and ribosomal RNA is known as the ________.

nucleolus

The _____ is the most prominent membrane-bound organelle in eukaryotic cells, and it houses most of a cell's DNA.

nucleus

Translation

occurs in ribosomes, RNA instructions are used to groups of groups of 3 nucleotides (codons) - codons create amino acids - once RNA sequence is fully translated, proteins begin to fold and form

Transcription

occurs in the nucleus, messenger RNA is created from DNA template

The signal transduction pathway allows ________.

one cell to regulate the gene expression of another cell

There are nearly 30 different disorders of sexual development. Who can have these disorders?

people with either XX or XY chromosomes

The physical traits of an organism are called its __________

phenotype

Assuming incomplete dominance, if a homozygous red-flowered plant is crossed with a homozygous white-flowered plant, what will be the color of the offspring?

pink

Annealing

primer bind to flanking regions of the target DNA sequence and begin to add free-floating nucleotides

The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?

prophase

During meiosis, segments of nonsister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur?

prophase I

The correct order of events during meiosis is ______

prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II.

A _______ is made up of hundreds or thousands of smaller units called amino acids, attached to one another in long chains.

protein

If an organism has two non-identical versions of a gene, the one that is not expressed in the organism is called the __________ allele.

recessive

What are telomeres?

regions of DNA at the end of chromosomes which do not code for making proteins

A _________ serves as the site of protein synthesis in the cytoplasm.

ribosome

What process involving cell division results in daughter cells that are NOT identical to the parent cell?

sexual reproduction

Before a cell divides, it copies all of its chromosomes. While the two copies of a chromosome are attached they are called ______ ___________.

sister chromatids

Hypothetically speaking, if a diploid sperm fertilized a diploid ovum, the zygote would be ____________.

tetraploid

What is crossing over?

the exchange of pieces of homologous chromosomes

Where in the mother's body does a developing embryo implant?

the uterus

A _______ is one particular variation of a character.

trait

____________ is the first step of gene expression, during which a particular segment of DNA is converted into RNA.

transcription

________ is the process in which mRNA codons are converted into an amino acid sequence.

translation

If genes are described as "sex linked," then they are ________.

typically on the X chromosome

Genital herpes is a sexually transmitted disease caused by a ________.

virus