Biology 1030 Exam 3- Espinoza Clemson
What is the life cycle of the cell?
A cell spends most of it's life in Interphase; this is when it is growing and developing. The other part of the cycle is spent in the mitotic phase; this is where it divides and new cells are formed.
What is binary fission?
A form of asexual reproduction in which the parent divides into two approximately equal parts
What is transduction?
A form of gene exchange by infection with a bacteriophage
What are autosomes?
Any chromosome that is not a sex chromosome
What are microfilaments?
Associated with cell membrane, they are dynamic structures. double helix of actin
At the end of meiosis I, the ploidy is _____.
Cut in half.
What is the material of a chromatin?
DNA and proteins.
What happens in prophase I?
Each replicated chromosome pairs with its corresponding homologous chromosome forming a tetrad. During tetrad formation, alleles can be exchanged between chromatids, a process called crossing-over.
What happens in anaphase I?
Homologous chromosomes separate
What is the G0 phase?
If the cell does not receive the go ahead for G1, it goes to G0 where it does not replicate. It is not dead though, just not dividing.
What happens in Meiosis I?
In meiosis I homologous chromosomes pair up, and each pair separates, producing two haploid cells with their sister chromatids still joined.
What is the difference between meiosis and mitosis?
Mitosis produces 2 daughter cells which are genetically identical to the parent cell. Each daughter cell is diploid (contains the normal number of chromosomes). This is the result of DNA replication and 1 cell division. ... Meiosis is used to produce gametes (sperm and egg cells), the cells of sexual reproduction.
What is the primary source of genetic variation?
Mutation
What is the haploid number?
N (23)
What is oogenesis?
Process by which ova are produced by the female.
A chromosome has _______ and ______.
Proteins and DNA
What are growth factors?
Proteins released by other cells that stimulate cells to divide.
When does DNA replication occur?
S phase of interphase
Every single pair of homologous chromosomes aligns _________.
independently
What is nondisjunction and when does it occur?
it's failure of my homologous chromosomes to separate during anaphase one of meiosis, it can result in gametes with odd numbers of chromosome orders, also non disjunction can affect any number of your chromosomes.
What is a euchromatin?
less condensed, transcriptionally active, sterically accessible form of DNA --EUchromatin is TRUly transcribed.--
What kind of DNA do eukaryotes have?
linear DNA
Does nondisjunction in meiosis I or meiosis II have more total abnormal gametes?
meiosis I
Can a heterochromatin be be transcribed?
no
Do centromeres split in Meiosis I?
no
Do neurons divide?
no
Does crossing over occur in prokaryotes?
no
What happens in telophase of mitosis?
nucleoplasm pinches off, chromosomes migrate to opposite sides of the cell, a nuclear envelope forms around each chromosome, nucleolous shows up, completely pinch off and you have two separate nucleus
What is a ploidy?
number of sets of chromosomes in a cell
How many nuclear divisions in mitosis?
one
What is a haploid?
one set of chromosomes
Does crossing over occur in mitosis or meiosis?
only in meiosis
What are homologous chromosomes?
paired chromosomes with genes for the same traits arranged in the same order
What is transformation?
process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria
What is spermatogenesis?
production of sperm
What is apoptosis?
programmed cell death
What is a kinetochore?
protein structure on chromatids where the spindle fibers attach during cell division to pull sister chromatids apart
What are some ways organisms reproduce asexually?
regeneration, budding, cutting/cloning
What happens in Anaphase II?
sister chromatids separate and move to opposite poles
What divides in mitosis?
somatic cells
What happens in meiosis II
splitting of sister chromosomes
what is the ploidy of secondary spermatocyte?
1n
What is the ploidy of primary oocyte?
2n
What is the diploid number?
2n (n=23)
What is Trisomy 21 (Down Syndrome)?
3 chromosomes on #21 most common cause of mental impairment, increases in likelihood w/ maternal age
What happens in metaphase I?
tetrads line up at metaphase plate
What does the reproductive behavior of cells (whether to divide or not) result from?
the interactions among many different molecules
What happens during genetic variation?
the loci changes and codes for different DNA sequences
What is a chromatin?
the material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA.
What is anchorage dependence?
the need for cells to be in contact with a solid surface to divide
What is a karyotype?
the number and visual appearance of the chromosomes in the cell nuclei of an organism or species.
What is a locus?
the precise location of a gene on a chromosome
Why do haploid organisms have mutations?
to get new alleles
What is conjugation?
transfer of DNA between bacteria using a pilus
How many nuclear divisions occur in meiosis?
two
What is a sister chromatid?
two identical chromatids.
What is the structure of a chromosome?
two sister chromatids held together by a centromere
What does sexual reproduction produce?
unique combination of genes
Do secondary spermatocytes have replicated chromosomes?
yes
Does each nucleus in the new daughter cells have the same # and same kind of chromosomes?
yes
In pro metaphase is the nuclear envelope gone?
yes
can an euchromatin be transcribed?
yes
A ______ is a single cell that comes from the product of fertilization
zygote
How do prokaryotes reproduce?
binary fission
Meiosis 1 stops at ______ and starts back again after _______.
birth, fertilization
What is crossing over?
breaking and joining with non-sister chromatid
cytokinesis in plant cells
cell plate forms
What happens in telophase II?
cells finna split.
Bacteria have genes on their _____ and on their _______.
chromosomes and plasmids
What happens in metaphase II?
chromosomes line up on metaphase plate
What are sex chromosomes?
chromosomes that determine the sex of an organism (XX- Female/XY-Male)
What happens in prophase II?
chromosomes, each consisting of two chromatids, become visible
What kind of DNA do prokaryotes have?
circular DNA, naked DNA, no nucleus
cytokenisis in animal cells
cleavage furrow and actin ring
What is a heterochromatin?
condensed, transcriptionally inactive, sterically inaccessible form of DNA --HeteroChromatin is Highly Condensed.--
What is the ploidy of primary spermatocyte?
diploid (2N)
What happens in cytokinesis?
division of the cytoplasm
When does crossing over occur?
during synapsis in meiosis I
What supports the egg?
follicular cells
What does meiosis produce?
gametes that have 1/2 the number of chromosomes as the parent does
What is a germ cell?
gametes, reproductive cells (sperm and eggs)
What does Meiosis II need to finish?
Sperm
What happens in meiosis I
Splitting apart of homologous chromosomes
How many cells do you end up with in mitosis?
TWO
What happens at the G1 checkpoint?
The cell checks that the chemicals needed for replication are present and for any damage to the DNA before entering S-phase
What happens in interphase I?
The cell undergoes a round of chromosome replication, and joins at the center
What is the G2 phase?
The period of the interphase where the cell produces proteins and organelles for the cell division.
What are eukaryotes chromosomes more complex?
They have internal membranes (nuclear), more and longer chromosomes (more DNA)
True or False: Unicellular organisms reproduce asexually.
True
Mutations are passed through ________ _______.
germ cells
What divides in meiosis
germ cells
What is a chromatid?
half of a chromosome
What is a diploid?
a cell that contains both sets of homologous chromosomes
What is the cell cycle control system?
a cyclically operating set of molecules in the cell that both triggers and coordinates key events in the cell cycle
What is a plasmid?
a genetic structure in a cell that can replicate independently of the chromosomes, typically a small circular DNA strand in the cytoplasm of a bacterium or protozoan. Plasmids are much used in the laboratory manipulation of genes.
What is density-dependent inhibition?
a phenomenon in which crowded cells stop dividing
What is the primary oocyte?
an immature sex cell that is able to undergo meiosis to become an egg cell
What is a somatic cell?
any cell of a living organism other than the reproductive cells. A body cell.
nondisjunction in Meoisis II
has fewer abnormal gametes (half)
