Chapter 8: The Cellular Basis Of Reproduction And Inheritance Flashcards
Asexual reproduction
Reproduction without sex
What happens during asexual reproduction
Parent cells divides only once to produce genetically identical daughter cells or offspring
How do prokaryotic cells reproduce?
Reproduce by asexually by binary fission
What prokaryotes reproduce by asexually/binary fission?
Bacteria and archaea
What is binary fission
Dividing into half
What is the process or three steps of asexual reproduction
1) duplication of chromosomes
2) continue elongation of the cell and movement of copies
3) division into two daughter cells
What are daughter cells
Are genetically identically to each other and parent cell
How do eukaryotic cells reproduce
By completing the cell cycle (mitosis)
The cell cycle includes
Interphase and mitotic phase
What is included in the interphase
G1,S, G2 phase
What is happening in interphase
Preparation of cells division
Most cells spend time in what phase
Interphase
What is happening in g0 phase
That is the resting phase
What cells stays in the g0 phase
Skeletal muscle and nerve cells
What is happening in g1 phase
Cells grows but doesn’t divide
S phase stands for?
Synthesis
What is happening in s phase
Cells duplicate its dna and chromosomes, duplication of Centrosomes begins
What is the first gap
G1
What does dna synthesis occur
S phase
What is the second gap
G2 phase
What is happening in G2 phase
Cells grows and compares for division and centrosome duplication ends
What is the m phase
Mitotic phase
What are the phases of mitosis
Prophase, prometaphase, metaphase, anaphase, telophase
What is happening in cytokinesis
Cytoplasm is dividing
What are somatic cells
All cells in our body except egg and sperm cells
Somatic cells are produced how
Asexually by mitosis
What allows us to grow and replace damaged/worn out somatic cells
Mitosis
What are gametes
Egg and sperm cells
What are other names for gametes
Sex cells or germ cells
How are gametes produced
By meiosis
Chromosomes are made up of what material
Chromatin
What is chromatin made up of
DNA and proteins
Each human has _____ chromosomes in somatic cells
46
Chromosome duplication occurs in what phase
S phase
Sister chromotids are produced in what phase
S phase
In s phase, 46 chromosomes turns into how many chromosomes and chromotids
46 chromosomes and 92 chromotids
What doesn’t change in the s phase? what does then?
of chromosomes, the appearance of chromosomes
What is the centromere
Constricted region that hold two sister chromatids together
In mitosis, that parent and daughter cells have _____ amount of chromosomes
Same
In G2 phase the cells has what inside the cell
Centrosomes
What are Centrosomes
Regions where micro tubes grow from
Each centrosome contains what
2 centrioles
What are centrioles made up of
Microtubles
Centrioles are only in…
Animal cells
In G2 phase, describe the nuclear envelope
It is still intact
In G2 phase, describe chromosomes
Each chromosomes consist of 2 identical sister chromatids
What are sister chromatids are held together at?
Centromere
In G2 phase, describe chromatin and chromosomes
They are loosely packed (decondensed)
Why are chromosomes loosely packed in G2 phase?
Due to chromatin being loosely packed
What is the first phase of mitosis
Prophase
Describe the nuclear envelope in prophase
It is still present
Describe chromosomes in prophase
They are tightly packed (condensed) with their sister chromatids
Are centrosomes present in prophase
Yes
What forms in prophase
Mitotic spindle beings to form
Mitotic spindle
Made up of spindle microtubules that guide the separation of chromosomes
What is the second phase of mitosis
Prometaphase
What happens to centrosomes in prometaphase
They are moved to the opposite poles of the cell
Describe chromosomes in prometaphase
They are still tightly packed
Describe nuclear membrane in prometaphase
It breaks apart and allows spindle to bind to chromosomes
Some spindle microtubles bind to ________
Kinetochores
What are kinetochores
Proteins
Where are kinetochores located
In the middle of sister chromatids
What is the third phase of mitosis
Metaphase
Describe centrosomes in metaphase
They are still present
What happens in metaphase
Mitotic spindle brings all chromosomes to the middle of the cell
Chromosomes align where in metaphase
On the metaphase plate, in the middle of the cell
What is happening with kinetochores during mitosis
They are facing the opposite poles of the spindle
What is the fourth phase of mitosis
Anaphase
Are centrosomes still present in anaphase
Yes
Describe what happens to sister chromatids in anaphase
They separate from each other and move to opposite poles of the cell
What are daughter chromosomes
The separation of sister chromatids from each other
Describe what happens with spindle microtubles in anaphase
The spindle attaches to kinetochores and the spindle gets shorter
What is the last phase of mitosis
Telephase
How many phases in mitosis
5
are centrosome still present in telophase
Yes
Describe what happens to nuclear envelope in telephase
Nuclear envelope reforms around each set of chromosomes
What happens to chromosomes in telephase
Chromosomes uncoil (decondense)
What happens to mitotic spindle in telephase
Disassembles
What happens after telephase
Cytokinesis occurs
In telephase what’s is causing the cell to try to become into 2 (from the inside of the cell)
The contracting ring
How does the cell divide from the outside
Cleavage furrow
What is the cleavage furrow
Is a contracting ring formed during animal cytokinesis
Cleavage furrow only occurs in ….
Animals (not plants)
Contracting ring is made up of
Actin filaments
When are two daughter cells fully separated
In cytokinesis
Daughter cell
Are genetically identical to each other and to parent cell
How do plants divide their cytoplasm
With cell wall
How do plants divide their cytoplasm
Cytokinesis
Cell plate
New cell wall that forms in the middle of the diving plant cell
What stimulates a cell to undergo mitosis
Growth factors
What are growth factors
Proteins that stimulate some cells to divides and some cells to grow
What are mitogens
Proteins that stimulate some cells to divide
What are the three ways to either start or stop mitosis
Growth factors, anchorage dependence of growth, and density dependent inhibition
What is anchorage dependence
Cell must be in contact with a solid surface to divide
Density dependent inhibition
Cells that are touched on all sides stop dividing
What are checkpoints
Point in the cell cycle where the cell stops to make sure that everything is okay before moving forward
How many checkpoints are there in mitosis
3
What are the names of the checkpoint
G1 checkpoint or r point, g2 checkpoint, m checkpoint
Where is the g1 or r point found
At the end of g1 phase
What is the purpose of g1 or r point checkpoint
To make sure cells is going and DNA is not damaged
G2 check point if found where?
Found at the end of g2 phase
What is the purpose of g2 checkpoint
Makes sure that the cell has duplicated its DNA and chromosomes
Where is the m checkpoint found
Found during mitosis of m phase
What is the purpose of m checkpoint
Makes sure that all chromosomes are aligned on metaphase plate
What happens if cells ignore the checkpoints
Tumors are created
What is a tumor
A mass of abnormally dividing cells, exhibiting uncontrolled cell division (mitosis)
Benign tumor
Tumor divides but doesn’t spread, non-cancerous
What are benign tumor
Non-cancerous
What is unique to benign tumors
Tumors are well defined, smooth edges
What are malignant tumors
Cancerous tumors invades surrounding tissues
What are unique to malignant tumors
Edges are no longer defined
Metastasis
Tumor uses blood and lymphatic vessels to invade other body parts. The tumor can travel to other body parts
What is a haploid
One set of chromosomes
How many chromosomes in a haploid cell
N=23
What’s an example of haploid cell
Egg and sperm
What is the union of egg and sperm
Fertilization
What is a diploid zygote
A fertilized egg
How many chromosomes in a diploid cell
2n=46
What cells only have germ line
Ovary and testis
Sexual reproduction involves what?
The exchange of genetic material such as DNA between gametes of 2 different types
What are the different types of gametes?
Egg and sperm
Mitosis produces
Body cells
Meiosis produces
Sex cells
Each gamete has _____ of chromosomes of parents cells
1/2
Meiosis
When parent goes through 2 rounds of cell division to produce 4 daughter cells, which are genetically different from each other and parent cell
Meiosis produces how many gametes
4
Meiosis goes through how many rounds of division
2 rounds
Mitosis produces how many daughter cells
2
How many rounds of division does mitosis goes through
1 round
Both meiosis I and II include what phases
Prophase, metaphase, anaphase and telophase
How many steps are in meiosis
4
What occurs before meiosis
Interphase
Meiosis I:
In prophase I what happens to the nuclear envelope
It breaks apart and mitotic spindle being to form
Meiosis I:
In prophase I, if there are 8 chromosomes, how many chromatids are there
16
Meiosis I:
In prophase I, what happens to chromosomes
They condense and form tetrads
What is synapsis
Homologous chromosomes pair up
Meiosis I:
In prophase I, each tetras consist how many chromatids and chromosomes
4 chromatids and 2 chromosomes
Where does crossing over occur
Prophase I, meiosis
In terms of chromosomes, where does crossing over occur
Homologous chromosomes
Homologous chromosomes
The same size, and have the same genes and loci (positions of genes on the chromosome), but not necessarily the same version of the genes
How are sister chromatids unique
They are identical
What can have same genes but different arrangement that can makes us have different features
Homologous chromosomes,
What is crossing over
Involves the exchange of DNA between non-identical(homologous) chromatids of homologous chromosomes
Crossing over occurs in what type of chromatids
Non identical sister chromatids
How does crossing over contribute to species diversity
Crossing over is one of the reasons we don’t look identical to our parents
Recombinant chromosome
New chromosome and is produced because of crossing over between gene I and gene II
What happens in metaphase 1
Homologous pairs meet in the middle
Independent assortment happens in what phase
Metaphase 1 of meiosis
What is independent assortment
Random alignment of maternal and paternal chromosomes of the metaphase plate
What are the process that makes sure we don’t look identical to our parents
Crossing over and independent assortment or chromosomes
Meiosis I:
In metaphase I, what aligns on the metaphase plate
Tetrads, pairs of homologous chromosomes
Meiosis I:
In metaphase I, spindle microtubles attach to what
Kinetochore
Meiosis I:
In anaphase I, what happens to sister chromatids
They are no longer identical due do crossing over.
Is there an interphase between meiosis I and meiosis II
Yes
What is different about interphase between meiosis I and meiosis II
Allows cell growth and centrosome duplication but no chromosomes are being duplicated
What is different between meiosis I and meiosis II
of chromosomes is reduced in half in meiosis II
What mistakes can occur in meiosis
Nondisjunction and aneuploid
Nondisjunction
Failure of homologous chromosomes or sister chromatids to separate properly during anaphase I or anaphase II
Aneuploid
Gametes have one less or one extra chromosomes
What are the different types of aneuploid
Monosomy and trisomy
Monosomy
One chromosomes is absent
Trisomy
Extra chromosome is present
Monosomy humans have how many chromosomes
45 chromosomes
Trisomic humans has how many chromosomes
47 chromosomes
What is the way we can find out if there is a mistake during meiosis
By getting a karyotype
What is a karyotype
Picture of all chromosomes in a single cell
Each human somatic cell is ______ (what kind of cell)…where does the chromosomes come from
Diploid, 46 chromosomes or 23 pairs. 23 from maternal and 23 from paternal
What are autosomes?
Non sex chromosomes, don’t determine sex of organism
What are chromosomes 1-22
Autosomes
What are sex chromosomes
The 23rd pair
What is important about the 23rd pair of chromosomes
Differs between female and male
What determines a human female
XX
What determines human male
XY
Human female 23rd pair homologous or non-homologous
Homologous
Human male 23rd pair homologous or non-homologous
Non-homologous
Karyotype analysis is good for what
1) determine gender
2) normal or abnormal # of chromosomes
3) length or size of chromosomes
If sperm only gave y, what would happen
There would be no daughters
What causes Down syndrome
Nondisjunction of chromosome 21 is the cause of Down syndrome
What is another name of Down syndrome
Trisomy 21
How many total chromosomes does a person with Down syndrome has
47 chromosomes, 3 copies @ #21
What is an example of autosomal abnormalities
Down syndrome
Autosomal abnormalities
Are abnormalities associated chromosome pair 1-22
Klinefelter syndrome
Trisomy, 47 chromosomes, abnormality within sex chromosome. XXY extra X chromosome
Is this abnormal XYY? What would happen
Yes, nothing (normal male)
Is this normal XXX? What would happen
No, nothing
Turner syndrome
X0, missing chromosome, always in girl cells. Ex of monsomy and has 45 chromosomes due to lack of X chromosomes
What abnormal sex chromosomes disease can’t have babies? They are sterile
Klinefelter and Turner syndrome
What is deletion
Part of the chromosome is deleted, making it shorter
What is duplication ? (That can affect an individual)
Part of the chromosome is duplicated, making it longer
Inversion
Segment of chromosome is broken in two places, reversed and put back together
Reciprocal translation
Nonhomologous chromosomes exchange region with each other creating two new chromosomes
What is the most common leukemia
CML, chronic myelogenous leukemia
What is leukemia
Cancer
CML affects what
Affects cells that give rise to white blood cells, leukocytes
How is CML formed
From a reciprocal translation in which part of chromosome 22 switches places with a small fragment from a tip of chromosome 9
CML, describe chromosome
Very short chromosome 22 also know as Philadelphia chromosome…attached to it is the activated cancer