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74 terms

Genetics First Exam

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Which two men are credited with?
the proposed the double helix structure of DNA
What is DNA?
a long, ladderlike molecule that twists to form a double helix.
Each strand of the helix is a linear molecule made up of subunits called.....
nucleotides
What are the four nitrogenous bases?
Adenine, Thymine, Guanine, and Cytosine
Adenine is to Thymine as Guanine is to.....
Cytosine
Guanine is to Cytosine as Adenine is to.....
Thymine
When does crossing over occur?
during prophase of meosis 1
What do homologus chromosomes get together in?
Temporary tetrads
What does meosis result in?
egg and sperm
Meosis also result in......
sex cells
What are the two sex cells that meosis can result in?
gametes or spores
Why does mitosis take place?
It takes the cell and Makes it Two (diploid)
What does mitosis result in?
identical twins
Where does mitosis take place?
Eukaryotes
How does mitosis take place?
parent cell -> DNA Replicates -> Two daughter cells
Why does meosis take place?
Meosis is the cell division process that enables the transformation from 2n to n
What does meosis have to do with?
sex
What does meosis result in?
egg and sperm (haploid)
Where does Meosis take place?
in eukaryotes
How does Meosis take place?
parent cell -> DNA Replicates -> Two daughter cells
-> Four daughter cells
How many cell divisions take place in mitosis?
one
How many cell divisions take place in meosis?
two
Why is meosis more complicated that mitosis?
-Gametes must contain precisely half the diploid number of chromosomes
-They must contain one of each homologus pair of chromosomes
What are the stages of Mitosis?
Interphase->Prophase->Metaphase->Anaphase
-> Telophase-> Cytokinesis
What us Gregor Mendel the father of?
Genetics (Transmission Genetics Specifically)
What was Mendel's Life Span?
1822-1844
What were Mendel's Experiments?
-Pea Plants; studied seven traits that bred true
-Transmission Genetics
What is a true-breeder?
A variety that produces the same trait over and over again
What where Mendel's Laws?
-Law of Segregation
-Law of Independent Assortment
-Theory of Segregation
What is the Law of Segregation?
During gametogenesis (meiosis), the paired factors segregate randomly so that half of the gametes received one factor and half of the gametes received the other
What is the Law of Independent Assortment?
During gamete formation, the segregation of any pair of hereditary determinants is independent of the segregation of other pairs
What is the Theory of Segregation?
-An individual inherit a unit of information (allele) about a trait from each parent
-During gamete formation, the alleles segregate from each other
What is the phenotypic ratio for dihybrid crosses?
9:3:3:1
What is the genotypic ratio for dihybrid crosses?
1:2:2:4:1:2:1:2:1
What is the phenotypic ratio for monohybrid crosses?
3:1
What is the genotypic ratio for monohybrid crosses?
1:2:1
What is a test cross?
individual that shows dominant (heterozygous or homozygous dominant) phenotype is crossed with individual with recessive phenotype
What is a punnett square?
This is a a visual of test crosses
Why did Mendell use the pea plant?
-Self-pollinating
-True breeding (different alleles not normally introduced)
-Can be experimentally cross-pollinated
What is an allele?
The exact same gene with a small difference (ex.mutation)
What is a somatic cell?
any cell of a living organism other than the reproductive cells
What are gametes?
sex cells
What does homozygous mean?
they have two identical alleles at a locus (AA or aa)
What does heterozygous mean?
the have two different alleles at a locus (Aa)
What is a phenotype the result of?
Gene Expression
What takes place during Gene Expression?
-Genes (DNA) are transcribed into RNA
-mRNA is translated into protein, tRnA & rRNA work in translation process
Eugenics?
The theory that humans can influence our own evolution, through selective breeding or genetic enhancement
What does ESLI stand for?
Ethical, Legal, and Social Implications; part of the Human Genome Project
What does locus mean?
the position on a chromosome of a particular DNA sequence gene
What is a genome?
a collection of all genetic material of organism
What is a genotype?
set of alleles present in the genome of an organism
What is a phenotype?
result of Gene Expression
What is a chromosome?
double stranded DNA molecule packaged by histone & scaffold proteins
What is a histone protein?
Any group of basic proteins found in chromatin
What is chromatin?
loose chromosome that interact with proteins during interphase?
What does genetics mean?
the study of heredity and the variation of inherited characteristics (ex: domestication of plants & animals)
What does diploid mean?
Chromosomal composition found in most female human cells (46 chromosomes)
What does haploid mean?
Chromosomal composition found in human gametes (23 chromosomes)
What does Karyotype mean?
phenotype of chromosomes
What are chromosome made of?
A single strand of DNA
What are genes made of?
Chromosomes; which are made of DNA
How many chromosomes are in a body cell?
46
How many nucleotide pairs (A-T, C-G) make up a human being?
about 3 billion
Why do all chromosomes in your body cells come in pairs?
Because we have two biological parents. One chromosome comes from mom; One chromosome comes from dad
How many pairs of chromosomes do you find in your body cells?
23 pairs
How many different kinds of chromosomes will you find in your body cells?
Two; autosomes and sex chromosomes
How many chromosomes do you find in your gametes?
23
Why is half the number of chromosomes in your body cells found in your gametes?
so that they create a normal (diploid) cell with 46 chromosomes
Which is bigger a gene or a chromosome?
Chromosomes are bigger than genes
Where are genes found?
on chromosomes
What two substances make up the sides of DNA?
sugar and phosphate
What matches with "A" on RNA?
Uracil
Why do homologous pairs of chromosomes split apart during meiosis?
so that each daughter cell only has 23 chromosomes; Anaphase Stage
What was the name of the monk who figured out basic genetics?
Gregor Mendel