Upload
tanya-hartman
View
22
Download
3
Tags:
Embed Size (px)
DESCRIPTION
Bellwork : Identify the following biomolecules. Science Fact of the Day: If the entire DNA from all nuclei in the human body were to be arranged lengthwise, it would measure 1,000 times greater than the distance from the Earth to the Sun. - PowerPoint PPT Presentation
Citation preview
Bellwork: Identify the following biomolecules
Science Fact of the Day: If the entire DNA from all nuclei in the human body were to be arranged lengthwise, it would measure 1,000 times greater than the distance
from the Earth to the Sun.
Objective: TLW understand the purpose of meiosis.
Language Objective: TLW take notes about meiosis and make a
Venn diagram of meiosis and mitosis.
Chromosomes
Chromosomes are coiled DNA located in the cell
nucleus.
An organism inherits one chromosome from each
parent.
How many parents do you have?
So you have ____ sets of each chromosome.
2 copies of each chromosome = homologous
chromosomes
A cell that contains 2 sets of homologous chromosomes is said to be diploid.
2N = diploid cell.Because N = number of chromosomes
Sexual Reproduction & Our Cells
On a cellular level, what happens during sex?
Biologically speaking, what’s the point of sex?
Sexual reproduction combines DNA from 2
parents.
Gametes are sex cells, also known as the sperm and
the egg.
When each parent forms gametes (egg, sperm) in their body, they can only
have 1 set of chromosomes instead of 2.
During fertilization, 1 + 1 = 2 sets of chromosomes.
When gametes (sex cells) are formed, there must be a process that separates the two sets of genes so that each gamete ends up with just one set.
Because gametes contain only 1 set of chromosomes they are said to be haploid.
N = haploid N= number of sets of chromosomes in the cell
Meiosis
Meiosis is a process in which the number of chromosomes per cell is cut in half through
the separation of homologous chromosomes in a diploid
cell.
** Meiosis is how gametes are produced**
Meiosis usually involves two divisions.
By the end of meiosis, the 1 diploid cell that entered meiosis has become four haploid cells.
During Prophase I of meiosis, chromosomes line up to form homologous pairs.
When crossing over occurs genetic material is exchanged between the maternal and paternal sets of chromosomes
present in the cell. Crossing over results in genetic variation.
Color and label the diagram
Dad’s chromosome
Mom’s chromosome
Crossing over
Result = genetic variation
Results of Meiosis
In male animals, the haploid gametes produced by meiosis are called sperm.
In female animals, the haploid gametes produced by meiosis are called eggs.
Mitosis vs. Meiosis
Mitosis results in two genetically identical diploid cells. Mitosis is used for growth.
Meiosis results in four genetically different haploid cells.
Meiosis is used for gamete production and increased genetic variation.
Title the next section of your journal, “Mitosis vs. Meiosis”.
Create a Venn diagram comparing and contrasting the processes of mitosis and meiosis. Consider the # of divisions, # of cells, haploid/diploid, function in the body, etc.
Now let’s talk about it…
Make sure your diagram
contains these
ingredients: