Science flashcards
In 1903 who was studying sex cells? What did he focus on?
Walter Sutton was studying cells.
He focused on the movement of chromosomes during the formation of sex cells.
What did Sutton hypothesize?
Sutton hypothesized that chromosomes were the key to understanding how offspring have traits similar to those of their parents.
What did Sutton find?
He found that the cells of a grasshopper have 24 chromosomes and the sex cells have only 12 chromosomes.
Explain the number of sex cells to body cells in a grass hopper.
Sutton found that sex cells have exactly half the number of chromosomes found in its body cells,
Sutton observed what happened when a sperm cell and an egg cell joined during fertilization. Describe it.
- The fertilized egg formed had 24 chromosomes
-had exactly the same number of chromosomes in its cells as did each of its parents.
The 24 chromosomes existed in 12 pairs. - One chromosome in each pair came from the male parent, while the other came from the female parent.
What is the chromosome theory of inheritance?
Genes are carried from parents to offspring on chromosomes.
What is meiosis? What happens during meiosis?
Meiosis is the process by which the number of chromosomes is reduced by half to form sex cells. During meiosis, the chromosome pairs separate and are distributed to two different cells.
What happens during meiosis (detailed)
- The resulting sex cells have only half as many chromosomes as the other cells in the organism.
- When the sex cells combine to form an organism, each sex cell contributes half the normal number of chromosomes
- the offspring gets the normal number of chromosomes- half from each parent.
What does a Punnet Square actually show?
The events that occur at meiosis.
When the chromosome pairs separate and go into different sex cells, so does what?
The alleles carried on each chromosome.
How many alleles from each pair go into each sex cell?
One
The body cells of humans contains how many chromosomes?
23 chromosome pairs or 46 chromosomes
How are genes lined up on a chromosome?
Chromosomes are made up of many genes joined together like beads on a string.
How many genes do human body cells contain? WHat do they do?
The human body contains about 35000 genes, and each control a trait.
Where are genes located?
On chromosomes
