Lab Test 2 Flashcards
Chromatin
Complex of DNA and protein that condenses during cell division
Somatic cells
Non reproductive cells. Have two sets of chromosomes
Cell cycle
The life of a cell from formation to its own division
Checkpoints
Where the cell cycle stops until a go ahead signal is received
Apoptosis
Programmed cell death
What is the significance of the S phase of interphase
During S phase, each chromosome replicates to produce two daughter copies, or sister chromatids. Proteins, such as histones, are synthesized. Duplication of centrioles is completed and they migrate to opposite poles. Microtubules that will become part of the spindle apparatus are synthesized
Why did early scientists call interphase the “resting phase”
Because they did not have the technology to see what actually occurred during this phase. The cell didn’t appear to be dividing so they assumed it was resting.
During cell division, how does interphase set up for prophase
DNA is replicated, important proteins are synthesized, and organelles are produced to supply each daughter cell. Structures to be used during cell division are also assembled. Cell division cannot be successful unless all these processes are carried out
What are several differences between animal and plant mitosis
In animal cell cytokinesis, the cell membrane constricts to pinch the parent cell into daughter cells. In plant cytokinesis, a new cell wall is fashioned between the new daughter cells. There are no centrosomes in plant mitosis
What are the three checkpoints of the cell cycle and the basic functions of each
G1: check for cell size, nutrients, growth factors, and DNA damage
G2: check for cell size and DNA replication
Spindle assembly checkpoint: checks for chromosome attachment to the spindle
What kinds of cells undergo meiosis
Only sex cells (gametes)
Compare and contrast meiosis and mitosis
Mitosis occurs in somatic cells and creates two genetically identical daughter cells that are diploid.
Meiosis occurs in sex cells creates 4 genetically unique haploid cells. It consists of 2 cell divisions
What is spermatogenesis. Where does it take place
The process in which spermatozoa are produced from spermatogonial stem cells by way of mitosis and meiosis
It occurs in the seminiferous tubules of the testes
Chromatin
a complex of DNA and protein that condenses during cell division
Somatic cells
Nonreproductive cells. Have two sets of chromosomes
Cell cycle
The life of a cell from formation to its own division
Checkpoints
Where the cell cycle stops until a go-ahead signal is receieved
Apoptosis
Programmed cell death
Centromere
The narrow “waist” of the duplicated chromosome where the two chromatids are most closely attached
Sister chromatids
Joined copies of the original chromosome that separate during cell division
Homologous chromosome
The cell has two sets of each chromosome; one of the pair is derived from the mother and the other from the father. The maternal and paternal chromosomes in a homologous pair have the same genes at the same loci, but possibly different alleles.
Cytokinesis
the division of the cytoplasm
Centriole
a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.
Spindle fibers
a structure made of microtubules that controls chromosome movement during mitosis
Asters
The asters synthesize and extend polymeric spindle fibers in a dividing cell
Cell plate
(in plant cells) a plate that develops at the midpoint between the two groups of chromosomes in a dividing cell and that is involved in forming the wall between the two new daughter cells
What is the difference between genotype and phenotype
Genotype is the gentic construction of a particular organism. Phenotype is the obervable characteristics of an organism resulting from the genotype
What are the chances of two parents who carry the gene for albinism (recessive) having a child without albinism
25% chance of having an offspring with albinism and 75% chance of having one without
Diploid
A cell that has two sets of chromosomes
Haploid
A cell that contains one set of chromosomes (gametes)
Meiosis I
reductional division): homologs pair up and separate, resulting in two haploid daughter cells with replicated chromosomes
Meiosis II
(equational division) sister chromatids separate
Fertilization
The union of gametes (sperm and egg)
Synapsis
In synapsis, homologous chromosomes loosely pair up, aligned gene by gene
Crossing over
Nonsister chromatids exchange DNA segments
Tetrads
Homologous chromosomes form tetrads when they pair with eachother
DNA
deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.
Components of nucleic acids
made from monomers known as nucleotides. Each nucleotide has three components: a 5-carbon sugar, a phosphate group, and a nitrogenous base
Universal recipient
AB. Can receive any blood type because they have no antibodies
Universal donor
O. Can donate to all because it has no antigens
Recessive
Heretible characteristics that are only expressed in offspring when inherited from both parents
Incomplete dominance
When one allele is not completely expressed over its paired allele. Creates a third phenotype which is a combination of the two alleles
Rh factor
The Rh factor is a type of protein on the surface of red blood cells. Most people who have the Rh factor are Rh-positive. Those who do not have the Rh factor are Rh-negative.
Nucleotides
a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.
ATGC or AUGC
Heterozygous
Having one of each two different alleles
Homozygous
When an individual had two of the same allele
Monohybrid cross
mating between two individuals with different alleles at one genetic locus of interest.
Genotype
The set of genes in an organism
Phenotype
Set of observable characteristics of an individual resulting from the genotype
Genes
a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.
Allele
one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
Dominant trait
One that is phenotypically expressed in heterozygotes
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.
Law of segregation
states that allele pairs separate or segregate during gamete formation, and randomly unite at fertilization.
Histones
highly alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes.
RNA
principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information.
rRNA
RNA component of the ribosome, and is essential for protein synthesis in all living organisms
tRNA
Transfer RNA that serves as the physical link between the mRNA and the amino acid sequence of proteins
DNA polymerase
enzymes that create DNA molecules by assembling nucleotides
RNA primer
short strand of RNA or DNA (generally about 18-22 bases) that serves as a starting point for DNA synthesis
Complementary base pairing
either of the nucleotide bases linked by a hydrogen bond on opposite strands of DNA or double-stranded RNA: guanine is the complementary base of cytosine, and adenine is the complementary base of thymine in DNA and of uracil in RNA.
What is gel electrophoresis
A technique that uses agarose, a polypeptide polymer derived from seaweed, to separate DNA by their size
What determines the banding in electrophoresis
The size of the DNA fragments determines the banding. The bands closest to the gel have the largest DNA fragments and the bands farthest from the gel have the smallest DNA fragments
How does gel electrophoresis work
A solution of DNA molecules is placed in a gel. Because each DNA molecule is negatively charged, it can be pulled through the gel by an electric field. Small DNA molecules move more quickly through the gel than larger DNA molecules
Law of independent assortment
when two or more characteristics are inherited, individual hereditary factors assort independently during gamete production, giving different traits an equal opportunity of occurring together.
Agglutination
The clumping of particles. Used in blood grouping
Antibodies
A large Y shaped protein used in the immune system to identify and neutralize pathogens
DNA replication
the biological process of producing two identical replicas of DNA from one original DNA molecule
Double helix
the structure formed by double-stranded molecules of nucleic acids such as DNA
Elongation
an enzyme called DNA polymerase adds DNA nucleotides to the 3’ end of the newly synthesized polynucleotide strand. The template strand specifies which of the four DNA nucleotides (A, T, C, or G) is added at each position along the new chain.
Initiation
proteins bind to the origin of replication while helicase unwinds the DNA helix and two replication forks are formed at the origin of replication
Termination
occurs when the two replication forks meet each other on the opposite end of the parental chromosome
Transcription
a particular segment of DNA is copied into RNA (especially mRNA) by the enzyme RNA polymerase
Translation
mRNA is transported out of the nucleus to the cytoplasm and directs protein synthesis
Mutation
occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene
DNA replication fork
Y shaped region where DNA strands are elongating
mRNA
Messanger RNA. convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression.
Anti A not present, anti-B present, anti-Rh present
B+
What is replication and why is it important
Replication is the process of producing two identical replicas of DNA from one DNA molecule. It is important for biological inheritance
What is the function of protein synthesis
Protein synthesis creates proteins. DNA is transcribed into mRNA. The mRNA is translated to produce a protein
What is meant by the semiconservative nature of DNA
One strand of the parent double helix is conserved in each new DNA molecule
Describe the steps of translation
The ribosome binds to mRNA at a specific area. The ribosome starts matching tRNA anticodon sequences to the mRNA codon sequence. Each time a new tRNA comes to the ribosome, the amino acid that it was carrying gets added to the elongating polypeptide chain
What is the potential danger of receiving the wrong type of blood during a transfusion
the antibodies in your blood will kill the new blood transfused
What causes the marbling effect in indian corn
transposons, or jumping genes
What distinguishes a sweet kernel and starchy
Sweet kernels (s) are wrinkled and dry. Starchy (S) are smooth
Interphase
the phase of the cell cycle in which a typical cell spends most of its life. During this phase, the cell copies its DNA in preparation for mitosis
Prophase
the chromosomes become visible as paired chromatids and the nuclear envelope disappears
Metaphase
the chromosomes become attached to the spindle fibers and line up at the equatorial plate
Anaphase
chromosomes move away from one another to opposite poles of the spindle.
Telophase
the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.
Cytokenisis
the cytoplasmic division of a cell at the end of mitosis, bringing about the separation into two daughter cells.
