Chapter 11 Flashcards
How are gametes formed?
They are formed by a process that separates the two sets of genes so that each gamete ends up with just one set
Who do offspring inherit their genes from, and how many copies do they receive?
They receive one copy of genes from each of their parents
How many chromosomes do all organisms have?
Trick question- All organisms have a different number of chromosomes
How many chromosomes does a fruit fly have?
It has 8 chromosomes
Define homologous
When half the chromosomes come from each parent
Define diploid
A cell that contains both sets of homologous chromosomes
What are the number of chromosomes in a diploid cell represented by?
The symbol 2N
Define haploid
A cell containing a single set of chromosomes/ genes
What cells in the human body are haploid?
The gametes contain only a single set of chromosomes/ only a single set of genes, therefore they are haploid
What are the number of chromosomes in a haploid cell represented by?
The symbol N
Define meiosis
Meiosis is a process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell
How many divisions does meiosis have?
It involves 2 divisions; meiosis 1 and meiosis 2
What has the original cell turned into by the end of meiosis 2?
The original diploid cell that entered meiosis has become 4 haploid daughter cells
What happens during the process of crossing over?
When homologous chromosomes form tetrads in meiosis 1, they exchange portions of their chromatids
What does crossing over produce?
A new combination of alleles
What can meiosis 1 be compared to?
Mitosis, except crossing over, because it produces 2 daughter cells
What cells enter meiosis 2?
The 2 haploid daughter cells produced by meiosis 1
What happens in meiosis 1 that doesn’t happen in meiosis 2?
Neither of the 2 daughter cells goes through chromosome replication before division
What does Meiosis 2 result in?
4 haploid (N) daughter cells
In male animals, what does meiosis result in?
4 equal sized gametes called sperm
Define fertilization
When male and female reproductive cells join to produce a new cell
Define true-breeding
It means a plant that can produce both sexually and asexually, and producing asexually produces an offspring identical to themselves
Define genetics
The scientific study of all things hereditary
Define hybrid
The offspring of crosses between parents with different traits
Define trait
A specific characteristic that varies from one individual to another
How many different traits of pea plants did Mendel study?
7
