Week 4 - Genetics to phases of meiosis Flashcards
is the scientific study of hereditary and variation
GENETICS
is the transmission of traits from one generation to the next
HEREDITY
- are the units of heredity, and are made up of segments of DNA
- are passed to the next generation
- most DNA is packaged into chromosomes
- one set of chromosome is inherited from each parent
GENES
each gene has a specific location called a _____ on a certain chromosome
LOCUS
one parent produces genetically identical offspring by mitosis
ASEXUAL REPRODUCTION
is a group of genetically identical individuals from the same parent
CLONE
two parents give rise to offspring that have unique combinations of genes inherited from the two parents
SEXUAL REPRODUCTION
human somatic cells have __ pairs of chromosomes
23
is an ordered display of the pairs of chromosome from a cell
KARYOTYPE
the two chromosomes in each pair are called __________ ___________ or homologs
HOMOLOGOUS CHROMOSOMES
chromosomes in a homologous pair are the ____ length and carry genes controlling the ____ inherited characteristics.
SAME
the sex chromosomes are called _ and _
X , Y
sex chromosome of human females
XX
sex chromosome of human males
XY
the 22 pairs of chromosomes that do not determine sex are called?
AUTOSOMES
contains a single set of chromosomes, and is haploid (n)
GAMETE
for humans, the haploid number is ?
23
in an unfertilized egg (ovum), the sex chromosome is always _?
X
in a sperm cell, the sex chromosome may be either?
X or Y
is the union of gametes
FERTILIZATION
the fertilized egg is called a?
ZYGOTE
the zygote produces somatic cells by _______ and develops into an adult.
MITOSIS
in MEIOSIS I, what separates?
HOMOLOGOUS CHROMOSOMES
in MEIOSIS II, what separates?
SISTER CHROMATID
the sister chromatids are genetically identical and joined at the?
CENTROMERE
WHAT PHASE IN MEIOSIS?
- typically occupies more than 90% of the time in meiosis
- chromosomes begins to condense
PROPHASE I
in ________, homologous chromosomes loosely pair up, aligned gene by gene
SYNAPSIS
a structure that forms between two homologous chromosomes during meiosis, specifically in prophase I
SYNAPTONEMAL COMPLEX
exhange of information of the homologous chromosomes
CHIASMA / CHIASMATA
WHAT PHASE IN MEIOSIS?
- tetrads line up at the metaphase plate, with one chromosome facing each pole
- homologous chromosomes lines up at the middle
- microtubules from one pole are attached to the kinetochore of one chromosome of each tetrad
METAPHASE I
WHAT PHASE IN MEIOSIS?
- pairs of homologous chromosomes separate
- one chromosome moves toward each pole, guided by the spindle apparatus
- sister chromatid remain attached at the centromer and move as one unit toward the pole
ANAPHASE I
WHAT PHASE IN MEIOSIS?
- each half of the cell has a haploid set of chromosomes; each chromosome still consists of two sister chromatids
- cytokinesis happens simultaneously
TELOPHASE I AND CYTOKINESIS
a phase of meiosis that is similar to mitosis
MEIOSIS II
WHAT PHASE IN MEIOSIS?
- spindle apparatus forms
- chromosomes (each still composed of two chromatids) move toward or makes it way to the metaphase plate
PROPHASE II
WHAT PHASE IN MEIOSIS?
- the sister chromatid are arranged at the metaphase plate
- because of the crossing-over in meiosis I, the two sister chromatids of each chromosome are no longer genetically identical
METAPHASE II
WHAT PHASE IN MEIOSIS?
- the sister chromatids separate
- the sister chromatids of each chromosome now move as two new individual chromosomes toward opposite poles
ANAPHASE II
WHAT PHASE IN MEIOSIS?
- the chromosomes arrive at the opposite poles
- nuclei form and the chromosomes begin decondensing
- cytokinesis separates the cytoplasm
- at the end of this phase, there are 4 daughter cells, each with a haploid set of unreplicated chromosomes
- each daughter cell is genetically distinct from the others and the parent cell
TELOPHASE II AND CYTOKINESIS
at anaphase I, it is __________ ___________, instead of sister chromatids that separate
HOMOLOGOUS CHROMOSOMES
what are the unique events that happens in prophase I?
SYNAPSIS and CROSSING-OVER
