Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
54 Cards in this Set
- Front
- Back
|
Genetics |
Scientific study of heredity and variation |
|
|
Heredity |
Transmission of traits from one generation to the next |
|
|
Variation |
Is demonstrated by the differences in appearance that offspring show from parents and siblings |
|
|
Genes |
Units of heredity, and are made up of segments of DNA |
|
|
How are genes passed |
Through reproductive cells called gametes |
|
|
Locus |
A genes specific location on a certain chromosome |
|
|
Asexual reproduction |
One parent produces genetically identical offspring by mitosis |
|
|
Clone |
A group of genetically identical individuals from the same parent |
|
|
Sexual reproduction |
Two parents give rise to offspring that have unique combinations of genes inherited from two parents |
|
|
Lifecycle |
Generation to generation sequence of stages in the reproductive history of an organism |
|
|
Human somatic cells (2n) have how many pairs of chromosomes |
23 |
|
|
Karyotype |
Ordered display/picture of the pairs of chromosomes from a cell |
|
|
The two chromosomes in each pair are called |
Homologous chromosomes or homologs |
|
|
Sex chromosomes |
X and Y (female: XX, male: XY) |
|
|
What are the 22 pairs of chromosomes that do not determine gender called |
Autosomes |
|
|
How many autosomes do humans have |
22 |
|
|
Each pair of homologous chromosomes include |
One chromosome from each parent |
|
|
The 46 chromosomes in a human somatic cell are two sets of |
23, one from the mother and one from the father |
|
|
Diploid cell |
(2n) has two sets of chromosomes, in humans 2N = 46 |
|
|
In a cell in which DNA synthesis has occurred each chromosome is |
Replicated |
|
|
Each replicated chromosome consists of |
Two identical sister chromatids |
|
|
How many sets of chromosomes do gamete cells contain |
One set, they are called haploid cells (N) |
|
|
Each set of 23 chromosomes consists of how many autosomes and how many sex chromosomes |
22 autosomes, 1 sex chromosome |
|
|
Sex chromosome in an undertakings egg (ovum) |
X |
|
|
Sex chromosome in a sperm cell |
Can either be X or Y |
|
|
Fertilization |
Union of gametes (egg and sperm) |
|
|
Fertilized egg is called a |
Zygote |
|
|
Typical eukaryote cell life cycle |
2N zygote, mitosis, growth, adult |
|
|
Gonads |
Ovum and testes, produce haploid gametes by meiosis |
|
|
Meiosis |
Reduction division, goes from two sets of chromosomes to only one set of chromosomes |
|
|
Do gametes go through any further cell division before fertilization |
No |
|
|
Alternation of generations in plants and some algae |
Life cycle includes both a diploidy and haploid multicellular stage, diploidy organism is called sporophyte, haploid organism is called gametophyte |
|
|
Do fungi and protists have a multicellular diploid stage |
No, most fungi and some protists do not have a multicellular Diploid stage |
|
|
Can haploid cells undergo meiosis |
No, only diploid cells can undergo meiosis |
|
|
Meiosis is preceded by |
The replication of chromosomes |
|
|
How does meiosis take place in terms of cell divisions |
Where is this occurs in two sets of cell divisions, meiosis I, and meiosis II |
|
|
How many daughter cells does meiosis results in |
Four |
|
|
Each daughter cell has how many chromosomes relative to the parent |
Each daughter cell has only half as many chromosomes as the parent cell |
|
|
Main event of meiosis I |
Homologous chromosomes separate |
|
|
Meiosis I results in |
Two haploid daughter cells with replicated chromosomes |
|
|
What happens in the second cell division, meiosis II |
Sister chromatids separate |
|
|
Meiosis II results in |
Four haploid daughter cells with on replicated chromosomes, it is calledthe equational division |
|
|
How is meiosis I like and different to mitosis |
Basically the same, except instead of sister chromatids being pulled apart, each pair of homologous chromosomes are pulled apart, and during metaphase I they form a double file line |
|
|
Three mechanisms in sexual reproduction that contribute to genetic variation |
Independent assortment of chromosomes at equator of metaphase I, crossing over, prophase I (synapsis/tetrad), random fertilization, the number of combinations possible and chromosomes of sort independently into gametes is 2^N, where N is the haploid number |
|
|
Random fertilization |
Any sperm could fuse with any ovum |
|
|
How does meiosis II compare to mitosis |
It is exactly the same save the fact that there is only half as many chromosomes |
|
|
Crossing over |
Unique event that only happens in meiosis I, parts of the DNA from each homolog is chromosomes switches over to the other chromosome in its pear, it cannot happen in meiosis II because the pairs of chromosomes are separated |
|
|
Synapsis |
Crossing over |
|
|
What is a tetrad |
Each pair of chromosomes form a group of four chromatids |
|
|
Chiasmata |
X shaped regions where crossing over occurred |
|
|
How do each of the four daughter cells formed in meiosis compared to the original parent cell |
They are genetically distinct or different |
|
|
Mutations |
Change in an organisms DNA, the original source of genetic diversity, |
|
|
What do mutations create |
Different versions of genes called alleles |
|
|
Recombinations |
Reshuffling of alleles during sexual reproduction produces genetic variation |
