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103 Cards in this Set

  • Front
  • Back
_____ happens exclusivly in Eukaryotes but not all
______ occurs at some stage of the life cycle,yeilding haploid genomes
During sex there is a ______ of 2 ______ genomes
The Fusion of 2 Haploid Genomes forms new individuals in multicellular organisms as a reult of fusion of _____ and ______.
This happens in both _____ and ______
egg and sperm;;plants and animals
Typical Animal Life Cycle:
______ occurs in germ line cells in gonads producing haploid gametes
All other cells are ______ cells
Gametes definition??
Eggs or Sperm
Somatic Cells??
Nonreproductive cells
Each gamete contain ___ chromosones while the Somatic cells of embryos and mature individuals contain ___
An egg and a sperm fuse together to form a single cell called a _______
The _______ contains 2 copies of each chromosone
The fusion of Gametes to form a new cell is called ________ or ________
If Reduction-Division did not occur,What would result?
Chromosone # would double with each Fertilization and # of chromosones in each cell would become impossibly Large
_______-_______ produces cells with half the normal # of chromosones
The Reduction-Division process is also known as _______
_____ and _______ together constitute a cycle of reproduction
Meiosis and Fertilization
2 sets of chromosones are present in the Somatic Cells of adult individuals making them _______.
Only 1 set is present in the Gametes,making them _______
Reproduction that involves this alternation of Meisosis and Fertilization is called ______ ________
Sexual Reproduction
In Sexual Reproduction,offspring inherit chromosones from ___ parents
The life cycles of all sexually reproducing organisms follow a pattern of alternation between _____ and ______ chromosone #'s but there is some ______ in the life cycle
Diploid and Haploid;Variation
Many type of algae spend the majority of their life cycle in a _____ state.
______ then _______
Haploid;Meiosis then Mitosis
In most animals,the ______ state dominates;the zygot first undergoes ______ then ______
Some plants and some algae alternate b/w a multicellular _____ phase and a multicellular ______ phase.
This process can also be called _______ of ________
Haploid;Diploid;Alternation of Generations
Cells not destined to form gametes are called ______ cells
In animals,the cells that will eventually undergo Meiosis to produce gametes are often referred to as ____ _____ Cells
Germ Line
In animals,both the somatic cells and the Gamete producing Germ Line Cells are _______.
Somatic Cells undergo ______ to form genetically identical diploid daughter cells.
Gamete Producing Germ Line Cells undergo ______ to produce Haploid Gametes
In the sexual life cycle,alternation of _____ and ______ generations occur
Meiosis is a process of cell divison where the # of chromosones in certain cells is halved during _____ ______
Gamete Formation
Some organisms have both prominent ______ and _____ stages.
This is AKA the ______ of _______
Haploid;Diploid;Alternation of Generations
In the Alternation of Generation,Haploid products of _____ divide by ______
Diploid products of ______ divide by _______
Some organisms have only 1 prominent stage which means NO _______ of ________
Alternation of Generations
In animals, the _____ stage is prominent and in Fungi the ______ stage is prominent
Reduction-Division occurs during _______.
In Meiosis there are 2 rounds of ______ and ___ Divisoin but only 1 round of ________
_____ is Preceded by 1 round of DNA Replication
Name 3 things that occur during Meiosis 1
Synapsis and Segregation of Homologues and Reduction-Division 2n---n
Segregation of Sister Chromatids and Formation of 4 Haploid Cells happen during which round of Meiosis?
Meiosis 2
During Meiosis 2,there is no ______ ________
Chromosone Replication
The most important difference in the behavior of chromosones b/w Meisosis and Mitosis,is that during MEIOSIS in ______ __,homologous pairs find eachother and become closely associated a process called pairing or _______
Prophase 1;Synapsis
Synapsis and Crossing Over occur in _______ of Meiosis 1
The association b/w the Homologues persists thruout ______ __ and dictates the ________ of the chromosones
Meisosis 1;Behavior
During _______ __ the paired Homolologues move to the metaphase plate and become oriented such that homologues are connected by their ________ to opposite poles of the spindle.
This is contrast to Mitosis where the behavior of the homologues is _______ of eachother
Metaphase 1;Kinetochores;Independent
During ______ __ homologues move to opposite poles for each pair of chromosones.
This is in contrast to Mitosis where _____ ______,not Homologues move to opposite poles
Anaphase 1;Sister Chromatids
The Reduction-Division process results in ___ homologue from each chromosone pair in each _______ cell.
The # of ______ has not been reduced but the # of _______ has
We count Chromosones,by counting _______
During ______ __,Genetic Recombination or Crossing Over also occurs
Prophase 1
______ ____ allows the homologues to exchange chromosonal material
Crossing Over
The sites of crossing over are called _______,and these sites of contact are maintained until _______ __
Chiasmata;Anaphase 1
The continued association of homologues until anaphase 1 is critical to the accurate _______ of _______
Segregation of Chromosones
Meisosis involves 2 succesive divisions with NO _______ of genetic material b/w them
Meiosis 2 is like ______
In Anaphase 1 of Meiosis 1 there is _______ ________
In Anaphase 2 of Meiosis 2 ther is _____ _______ ______
Chromosone Segragation;Sister Chromosone Segregation
In Prophase 1 of Meiosis,the DNA coils ______ and individual chromosones first become _______
In ______ __ Homologous chromosones become closely associated in synapsis,exchange segments by crossing over,and then seperate
Prophase 1
During Prophase the ____ of the chromatids attatch to the _____ envelope at specific sites
Homologue pairs line up side by side,guided by heterochrmatin sequences,in the process called ______
_______ _____ are thought to contain the enzymatic machinary necessayr to break and rejoin homologous chromatids
Recombination Nodules
Crossing Over involves a complex series of events in which DNA Segments are _____ b/w __-_____ chromatids
exchanged;Non-Sister Chromatids
Crossing Over b/w _____ _____ is suppressed during Meiosis
Sister Chromatids
Human Chromosones typically have ___ or ___ crossovers
2 or 3
When Crossing Over is complete homologous chromosones are ______ from the Nuclear Envelope and begin to move ____ from eachother
At the point where Crossing Over is complete,there are __ chromatids for each type of chromosone.
Which means there are ___ homologous chromosones,each of which consists of __ sister chromatids.
The 4 chromatids at the end of Crossing over do not _______ completely
During Prophase 1, there is a complete ______ of replicated homologs
______ occurs thruout an entire length of a pair of homologus in prophase 1
_______ is the key to chromosone segregation
______ _____ is the recpricol echange b/w nonsister chromatids
Crossing Over
Crossing Over is a type of ________,it mixes maternal and paternal genes
What is the visual evidence in Crossing Over ?
A ______ is a crossover b/w nonsister chromatids,stabalized by sister chromatid cohesion
The precense of a Chiasma indicates that 2 chromatids have _______ ______
exchanged parts
The Chiasmata move to the end of the chromosone arm before ______ __
Metaphase 1
By ______ __, the nuclear envelope has dispersed and the microtubules form a spindle
Metaphase 1
______ ______ holds the homologous chromosones together in metaphase 1
Terminal Chiasmata
Microtubules attatch to kinetochore proteins only on the ______ of each centromere
The orientation of each pair of homologues on the spindle axis is ______
_______ play an important role in alighning the chromosones on the metaphase plate
During _______ __ the homologues are pulled apart.
Anaphase 1
Meiosis 1 results in the _______ _______ of maternal and paternal chromosones into the Gametes
Independent Assortment
During Anaphase 1,each ______ moves to 1 pole taking both sister chromatids with it
Dirng Anaphase 1,______ ______ do not seperate
Sister Chromatids
By the beginning of _______ __,the chromosones have segregated into 2 clusters.1 at each pole of the cell
Telophase 1
In _______ __,the nuclear membrane reforms around each daughter nucleaus
Telophase 1
The _______ checkpoint insures proper attatchment
A ________ event initiates motor activity and anapahase
Meiosis 2 is ______ similar to Mitosis
During ______ __,each nuclear envelope breaks down as a new spindle forms
Prophase 2
In ______ __,spindle fibers bind to both sides of the centromeres
Metaphase 2
During _______ __,the spindle fibers contract and centromeric sister chromatid cohesion is realesed,splitting the centromeres and moving the sister chromatids to opposite poles
During _______ __,the nuclear envelope reforms around the 4 sets of daughter chromosones
Telophase 2
In animals,the 4 haploid cells produced at the end of Meiosis 2,diffrentiate into _______
In plants and many other organisms the 4 haploid cells produced by Meiosis divide by _______,followed sometime later ______ formation
In ______ reproduction,an individual inherits all of its chromosones from a single parent and is genetically identical to its parent
Asexual Reproduction
Not all reproduction is ________
_______ cells reproduce asexually
Most protists reproduce asexually except under stress where they switch to ______ _______
Sexual Reproduction
Even when Meiosis and production of Gametes occur,reproduction may still take place w/o ____
The development of an adult from an unfertilized egg is called ________
During Sex,______ destroys advantegeous combinations
Name 3 consequences of Sex that each help generate genetic diversity
Independent Assortment,Crossing Over and Random Fertilization
_______ can be destructive
Only a _____ cell can repair certain kinds of chromosone damage
During Random Fertilization,Qualities of Gamete usually do not reflect qualities of ____ enclosed in Gamete
The close assocition of homologues during Meiosis may have evolved as a mechanism to repair _______ _______
Chromosonal Damage