Exam 2 Flashcards
True or False: Most mutations cause problems
False
Mitosis occurs in 4 stages. Select the correct sequence.
Prophase, metaphase, anaphase, telophase
If an organism has a diploid number of 16, how many chromatides are visible at the end of mitotic prophase? How many chromosomes are moving to each pole during anaphase of mitosis?
32, 16
True or False: A missense mutation is a change in one DNA base pair that results in the substitution of one amino acid for another in the protein made by a gene
True
True or False: In mitosis, each daughter cell receives a haploid set of chromosomes identical to parental cell.
False
True or False: A nonsense mutation often results in a shortened protein function improperly or not at all
True
True or False: Autosomal chromosome pairs are identical, whereas the sex chromosome pair in males is not.
True
The process of meiosis results in
Doubling the chromosome number
Two diploid cells
No change in the chromosome number for parent cells
The production of 4 identical cells
A reduction in the chromosome number
In the cell cycle, the G1 phase represents
A period of growth
Autosomes represent
All chromosomes other than the sex chromosomes
During meiosis in an organism where 2n=8, how many chromatids will be present in a cell at the beginning or meiosis II?
8
True or False: Mutations in a germ cell are passed on only to other germ cells in members of future generations
False
True or False: Control systems in the cell induce cell suicide, or apoptosis, in cells with excessive DNA damage.
True
Mutations are changes in the nucleotide sequence of DNA that
Can be passed on to daughter cells
In the general public, mutations are
Rare
True or False: Most mutations happen in the region of the DNA known as a gene
False
True or False: If a mutation happens in a gene, it is usually bad for the organism
True
True or False: If a parent gets cancer in the skin cell from too much sun, that mutation can be passed to offspring
False
Which mutations will be passed on by cell division in other body cells but cannot be transmitted to future generation?
Mutations in the body cell (somatic cell)
Which mutations are passed on to all the cells of future generations?
Mutations in germ cells
Mutations of a germ cell can be:
- mutation of a single nucleotide change in the DNA
- deletion or insertion of one or more base pairs
- alteration in the structure of the chromosome
What factors influence mutation rates?
- Gene size: larger faster
- Nucleotide sequence
- Spontaneous mutations
- Induced mutations
Name the type of mutation that are the result of erred in normal cellular processes, such as DNA replication, or are the result of natural changes in the molecular structure of the bases in DNA.
Spontaneous mutations
Type of mutations by the action of environmental agents called mutagens that attack DNA or disrupt the cellular process. Mutagens include radiation and chemicals.
Induced
Which enzyme incorrectly reads the nucleotide on the template strand and inserts the wrong nucleotide into the new DNA strand during mutations in DNA replication?
Polymerase
What changes in hydrogen bonding properties of bases allow bonding with noncomplimentary bases and can cause mutations in DNA?
Tautomeric shifts
What are base analogs?
Mutagenic chemicals that resemble nucleotides and are incorporated into DNA or RNA during synthesis
Name the mutational events in which a number of bases (other than multiples of three) are added or removed from DNA, causing a shift in the codon reading frame
Framshift mutations
What is a common reason for Hgb mutations?
Nucleotide mutations
Which mutations produce elongated proteins?
Sense mutations
Which mutations produce shorter proteins?
Nonsense mutations
What type of mutations are responsible for 5-10% of all known mutations?
Frameshift mutations
What phenomenon expands the number of repeats within a gene converting a normal allele into a mutant allele?
Allelic expansion: increase in gene size caused by an increase in the number of trinucleotide repeat sequence
What are the fates of damaged DNA?
- dormancy
- apoptosis or cell suicide
- accumulated mutations cause the cell to escape the normal controls of the cell and become cancerous
175 DNA repair genes encode enzymes that monitor and repair DNA damage and mutations
What is the name of the regulatory region located at the beginning of a gene?
Promoter
Term describing selective expression of either the maternal or paternal copy of a gene
Genetic imprinting
Which receptors on hypothalamic cells sense the level of stress hormones and signal the adrenal gland to slow the release of stress hormones bringing the body back into balance?
Glucocorticoid receptors (GRs
The study of the chemical modifications of chromosomal DNA (such as methylation of bases) and/or associated histone proteins that change the pattern gene expression without affecting the nucleotide sequence of the DNA.
Epigenetics
A term describing a phenotype that is produced by epigenetic changes to DNA.
epigenetic trait
What defines the epigenetic state of the cell?
epigenome
Do epigenetic modifications change the nucleotide sequence?
Unlike mutations, which involve a change in the DNA sequence, epigenetic modifications do not change the nucleotide sequence, but they do affect how genes behave.
Large cellular polymers assembled by chemically linking monomers together
macromolecules
Macromolecules including sugars, glycogen, and starches composed of sugar monomers linked and cross-linked together
carbohydrates
A class of cellular macromolecules including fats and oils that are insoluble in water
lipids
A class of macromolecules composed of amino acids monomers linked together and folded into a three-dimension shape
Protein
A class of cellular macromolecules composed of nucleotide monomers linked together. There are two types of nucleic acids DNA and RNA which differ in the structure of the monomers.
Nucleic Acid
Structures composed of two or more atoms held together by chemical bonds
Molecules
Cytoplasmic structures that have a specialized function
Organelles
A system of cytoplasmic membranes arranged into sheets and channels whose function it is to synthesize and transport gene products
Endoplasmic Reticulum (ER)
Cytoplasmic particles that aid in the production of proteins
Ribosomes
Membranous cellular organelles composed of a series of flattened sacs. They sort, modify, and package proteins synthesized in the ER.
Golgi complex
Membrane-enclosed organelles in eukaryotic cells that contain digestive enzymes
Lysosomes
Membrane bound organelles, present in the cytoplasm of all eukaryotic cells, that are the sites of energy production
Mitochondria (singular mitochondrion)
The membrane bound organelles in eukaryotic cells that contain the chromosomes
Nucleus
A nuclear region that functions in the synthesis of ribosomes
Nucleolus (plural: nucleoli)
The DNA and protein components of chromosomes, visible as clumps or threads in nuclei
Chromatin
The threadlike structures in the nucleus that carry genetic information
Chromosomes
In humans, the X and Y chromosomes that are involved in sex determination
Sex chromosomes
Chromosomes other than the sex chromosomes in humans, chromosomes 1-22 are these
Autosomes
The sequence of events that takes place between successive mitotic divisions
Cell cycle
The period of time in the cell cycle between mitotic divisions
Interphase
Form of cell division that produces two cells, each of which has the same complement of chromosomes as the parent cell
Mitosis
The process of cytoplasmic division that accompanies cell division
Cytokinesis
The stage of interphase that begins immediately after mitosis, RNA, proteins, and organelles are synthesized
G1 (Gap 1)
The stage of interphase where DNA is replicated and chromosomes form sister chromatids
S (Sythesis)
The stage of interphase where mitochondria divide. Precursors of spindle fibers are synthesized.
G2 (Gap 2)
The stage of mitosis where chromosomes condense, nuclear envelope disappears, centrioles divide and migrate to opposite poles of the dividing cell, and spindle fibers forms and attach to chromosomes
Prophase
The stage of mitosis where chromosomes line up on the middle of the dividing cell
Metaphase
Stage of mitosis where chromosomes begin to separate
Anaphase
Stage of mitosis where chromosomes reach opposite poles, new nuclear envelope forms, and chromosomes decondense
Telophase
One of the strands of a duplicated chromosome, joined by a single centromere to its sister
Chromatid
A region of a chromosome to which spindle fibers attach during cell division. The location of the centromere gives a chromosome it’s characteristic shape.
Centromere
Two chromotides joined by a common centromere Each chromatid carries identical genetic information
Sister chromatids
The process of cell division during which one cycle of chromosomal replication is followed by two successive cell divisions to produce four haploid cells
Meiosis
The condition in which each chromosome is represented twice as a member of a homologous pair
Diploid (2n)
The condition in which each chromosome is represented once in an unpaired condition
Haploid
Chromosomes that physically associate (pair) during meiosis. Have identical gene loci.
Homologous chromosomes
The results of meiosis I that puts random combinations of maternal and paternal chromosomes into gametes
Assortment
A process in which chromosomes physically exchange parts
Crossing over
The stage of meiosis when chromosomes become visible, homologous chromosomes pair, and sister chromatids become aparent. Recombination takes place.
Prophase I
The stage of meiosis where paired chromosomes align at the equator of cell
Metaphase I
The stage of meiosis when paired homologous chromosomes separate. Membranes of each chromosomes pair move to opposite poles
Anaphase I
The stage of meiosis where chromosomes uncoil and become dispersed
Telophase I
The stage of meiosis where cystoplasm divides forming two cells
Cytokinesis
The stage of meiosis where chromosomes recoil, shorten
Prophase II
The stage of meiosis when unpaired chromosomes become aligned at the equator of the cell
Metaphase II
The stage of meiosis when centromeres separate. Daughter chromosomes, which were sister chromatides, pull apart.
Anaphase II
The stage of meiosis when chromosomes uncoils, nuclear envelope reforms. Meiosis ends.
Telophase II
The stage of meiosis when the cytoplasm divides, forming daughter cells
Cytokinesis
one of the possible alternative forms of a gene, usually distinguished from other alleles by its phenotypic effects.
Allele
Mitotically active cells in the gonads of males that give rise to primary spermocytes.
Spermatogonia
The four haploid cells produced by meiotic division of a primary spermatocyte
Spermatids
Cells that produce primary oocytes by mitotic division
Oogonia
The cells produced from oogonia that will begin meiosis during the embryogenesis
Primary oocyte
The large cell produced by the first meiotic division
Secondary oocyte
The haploid cell produced by meiosis that becomes the functional gamete
Ovum
Cells produced in the first and second meiotic division in female meiosis that contain little cytoplasm and will not function as gametes
Polar bodies
The fundamental unit of heredity and the basic structural and functional unit of genetics
Gene
The trait expressed in the F1 (or heterozygous) condition
Dominate trait
The trait unexpressed in the F1 but re-expressed in some members of the F2 generation
Recessive Trait
The observable properties of an organism
Phenotype
The specific genetic constitution of an organism
Genotype
Having identical alleles for one or more genes
Homozygous
Carrying two different alleles for one or more genes
Heterozygous
The separation of members of a gene pair from each other during gamete formation
Separation
The random distribution of genes into gametes during meiosis
Independent assortment
The position occupied by a gene on a chromosome
Locus
A diagram listing the members and ancestral relationships in a family; used in the study of human heredity
Pedigree
First affected family members who see medical attention for a genetic disorder
Proband
Expression of a phenotype that is intermediate to those of the parent
Incomplete dominance
Full phenotypic expression of both members of a gene pair in the heterozygous condition
Codominance
Genes that have more than two alleles
Multiple alleles
The interaction of two or more non-alleleic genes to control a single phenotype
Epistasis
