Question | Answer |
heredity | passing of traits from parents to offspring |
trait | an inherited characteristics of an organism |
allele | one of the different forms of a trait |
chromosome | a rod or x shaped structure made of DNA |
gene | a section of DNA that contains the information of one trait |
genetics | study of heredity |
dominant | A gene that determines a phenotype in combination with another gene it can mask other forms |
recessive | a gene that is only expressed if there are no other dominant genes present, otherwise they are hidden or masked |
homozygous | having two identical alleles for a trait (they are the same) |
heterozygous | having one dominant and one recessive allele for a trait (they are different) |
genotype | combination of genes for a trait |
phenotype | way the genes are expressed, the way the organism appears for a trait |
mitosis | nuclear division producing two identical cells with full number of chromosomes |
meiosis | nuclear division producing four (non-identical gametes) with half the number of chromosomes |
gamete | a sex cell (involved in sexual reproduction) |
sperm | the male gamete |
egg | the female gamete |
somatic cell | a normal body cell, not a gamete |
fertilization | the union (joining) of a male gamete and a female gamete |
zygote | the cell resulting from fertilization |
Punnett square | tool used to predict gene combinations and expressed traits of an offspring |
Who was Gregor Mendel? | a monk in Australia, born in 1822 |
What did Mendel study | garden peas, lifted the confusion on how traits are passed on from one generation to the next |
An upper case letter represents what? | the dominant gene. for example he used "T" to describe the dominant Tallness gene |
lower case letter is for what? | recessive gene |
What happens with mitosis occurs in humans? | all 23 pairs of chromosomes duplicate and a full se of chromosomes passes into each daughter cell. |
Why is mitosis important | because we need exact copies of cells to replace old or dying cells throughout our bodies |
What happens in sexual reproduction | a new individual is formed that has different looks, abilities, and behavior from its parents |
what happens in meiosis | parents produce sex cells (eggs or sperm) that contain exactly half as many chromosomes as body cells. |
each male sex cell (sperm)has how many single chromosomes? | 23 single chromosomes |
each female sex cell (egg) has how many single chromosomes | 23 single chromosomes |
How many possible combinations can genes be paired | 4 |
Who is Reginald Punnett | English Geneticist at Cambridge University |
What did Reginald Punnett do? | developed a way to display the possible ways that genes could pair during genetic cross |
What was the display called that Reginald Punnett developed? | "Punnett square" |
What did the Punnett square look like | a large box divided into four small boxes |
Where do you write the trait from the female parent in the Punnett square? | above the square |
where did the same trait for the male parent go | left of the square |
what did you write inside the squares | the possible outcomes |
What does the Punnett square show? | the probability that specific genotypes will occur (it does not predict which gene will become the offspring's genotype) |
Who is Dolly | a sheep that was cloned in march 1997 |
How was Dolly created | from the DNA of just one parent |
Dolly is from what species | a white sheep called Finn Dorset |
How are identical twins formed? | from a single Zygote, they have identical genes |
how are fraternal twins formed | from two different fertilized eggs. fraternal twins are not identical. they are like same ages sibling's. they do not have identical genes |