Chaptre 6 Flashcards
Genetic diversity?
Inherited genetic differences in a species that give many organisms a survival advantage.
Sexual reproduction?
Reproduction that require two parents and produces off springs that are genetically different from each other, from either parent and from any other member of their species.
Diploid number?
Two sets of chromosomes, the diploid numbers for a human cell is 46
Haploid number?
Each set of inherited chromosomes, half the diploid number (n); humans inherit of 23 chromosomes and one set of 23 chromosomes from their male parents.
Gametes?
Specialized cells necessary for reproduction in a animal, male gametes are sperms and in females they are eggs.
Fertilization?
The process during which an egg cell is penetrated by a sperm cell and the haploid genetic information of both males and females gametes combines.
Embryo?
The stage of a multicellular organism that developed from a zygote.
Meiosis?
The process that produces gametes with half the number of chromosomes as body cells.
Homologous chromosomes?
A pair of matching chromosomes.
Crossing over?
An event in meiosis 1 in which sister chromatids exchange DNA results in variations in gametes.
Independent assortment?
An event in meiosis 1 in which homologous pairs of chromosomes separates and sort themselves into a daughter cells a shuffling of genes that contributes to variations and genetic diversity.
Karyotype?
A photo micrograph that shows the number of chromosomes a person has, as well as their size and shape, prepared by cutting and pasting chromosomes taken from body cells during mitosis; used to diagnose genetic disorders.
Syndromes?
A particular disease or disorder with a specific group of symptoms that occur together.
Mating?
The process by which gametes arrive in the same place at the same time.
External fertilization?
Fertilization in which a sperm cell and an egg cell unite outside the bodies of the parents.
Internal fertilization?
Fertilization in which sperm cells are deposited inside the females body where they meet egg cells.
Pollination?
The transfer of males gametes in pollen from the male reproductive part of a plant to the female reproductive part of a plant.
Ovules?
The female plant structures that contains eggs cells.
Pollen tube?
A structure that delivers sperm cells to egg cells in plants formed after pollen lands on the female part of a plant.
Crossing over?
Crossing over is when a chromosomes pair in meiosis exchange DNA. as a result the chromosomes pick up new genetic DNA. multiple cross overs can occur.
Independent assortment?
It occurs in meiosis 1
Homologous chromosomes separate at the equator and move towards opposite poles of the cell.
For each 23 pairs there are two possibilities for how chromosome will eventually sort itself into daughter cells.
Gamete formation?
Although the process of meiosis is the same for males and females gamete formation is different. In males meiosis 1 occurs and produces 2 cells. Followed by meiosis 2 where those two cells slit equally. In females 2 eggs are produced in meiosis 1 but the division is unequal. One of them has more cytoplasm and organelles. When those eggs go and slit agin they end up with three smaller eggs and 1 super one.
What the function of meiosis?
The process where cells are produced with half as many chromosomes as normal.
Haploid number in humans?
23
Diploid number in humans.
46
What are zygotes?
A fertilized egg.
What are homologous chromosomes?
Chromosomes that cross over and exchange DNA
Compare the number do chromosomes in an egg cell VS a skin cell.
There is half as many
What characteristics can you use to indenting homologous chromosomes?
They are the same shape, size and have genes in the same spots.
What benefits to genetic diversity?
Species can not all be affected by disease or mutation. We are all different.
How does a zygote become an embryo?
By going through mitosis.
What stage meiosis are these thing in?
- homologous Chromosomes pairs go to the equator
- individual chromosomes go to the equator
- crossing over occurs
- homologous chromosomes go to opposite poles?
- centromeres divide?
1 2 1 2 2
What the difference between chromosomes in mitosis and meiosis 1?
In meiosis have exchanges DNA
How does the number of chromosomes in metaphase compare to the number in metaphase 2 meiosis?
There is half the number in metaphase 2
Explain how crossing over can creat genetic diversity?
Because the chromosomes are exchanging DNA creating a pattern that hasn’t been created yet.
Give an example of a chromosomes mutation?
Part of the chromosomes will be missing resulting in serious things such as blindness or a defeat.
How can chromosomes be lost or added?
Because of a mutation
Why is meiosis so important?
Other wise we would all be double the genetics because our gametes wouldn’t have divided twice.
Prophase 1?
Homologous chromosomes pair up and non sister chromatids exchange DNA, this process is called crossing over.
Metaphase 1?
Homologous pairs arrange and pair up at the equator.
Anaphase 1
Homologous chromosomes separate and are pulled to opposite poles by the spindle fibres.
Telophase 1?
One chromosomes from each homologous pair is at each end of the pole
Interkinesis?
It is the stage between cells division stages. During this time the cell will grow and make proteins like interphase. There is no replication of DNA during this stage.
Prophase2
There is one chromosomes from each homologous pair in each cell.
Metaphase 2
X shapes chromosomes form a single line across the middle of the cell.
Anaphase?
Sister chromatids move to opposite poles of the cell. Once they separate each sister chromatid is considered to be a chromosome.
Telophase 2?
Spindle fibres begin to disappear and a nuclear membrane forms around each set of chromosomes.
Egg and sperm cells have substances on their surface that aid in species identification. What are these substances?
A sugar like coating.
What is the method of fertilization for land dwelling animals?
Internal fertilization.
What is the method for water dwelling animals?
External fertilization
What is pollination?
It is the transfer of male gametes in structures called pollen from the male part of the reproductive plant to the female part.
What is the anther?
The place in the plant where pollen is produced.
What are pollen grains?
Cases containing male gametes.
Filaments?
Stalk that supports the anther
Stigma?
Sticky lip of the pistil that captures pollen grains.
Style?
Stalk that supports the stigma and in which the pollen tubes form.
Ovary?
Swollen base of the pistil containing ovules
Ovules?
Sacs containing gametes.
How is pollen transferred?
Through the wind.
What can be found inside of a seed?
Gametes
What is embryonic development?
The early development of an organism.
What months of the pregnancy does embryonic development take place in children.
The first two months
Does the zygote under go mitosis before or after it is fertilized?
After
After the zygote divides and under goes mitosis what size does it become and what is its new name?
It is 0.2 mm and it is called a morula.
What is the stage after morula and what size does it become.
A hallow ball of cells form which is called a blastula and it is 1.5mm in diameter.
What can a blastula also be used for or called?
An embryonic stem cell and it can be used to be any cell in the body.
What happens during gestural?
The blastula organizes itself into three layers.
What is the outside layer of the gastrula called?
The ectoderm
