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Sex cells, also called gametes, use meiosis to divide
Sex cells, also called gametes, use meiosis to divide
Driving questions: There are two types of cell division, mitosis and meiosis. Which types of cells use mitosis and which use meiosis? How are the chromosome numbers different? Which process produces identical cells and which produces variation (different cells)?
Driving questions: There are two types of cell division, mitosis and meiosis. Which types of cells use mitosis and which use meiosis? How are the chromosome numbers different? Which process produces identical cells and which produces variation (different cells)?
Meiosis is a special type of cell division, used only by __________________ cells, also called ______________________.
Meiosis is a special type of cell division, used only by __________________ cells, also called ______________________.
Mitosis is used by all other cells, called ____________________ cells, also called _____________________ cells.
Mitosis is used by all other cells, called ____________________ cells, also called _____________________ cells.
In humans, all cell division starts with a cell containing 46 chromosomes.
In humans, all cell division starts with a cell containing 46 chromosomes.
In meiosis, how many chromosomes does each daughter cell have? ___
In meiosis, how many chromosomes does each daughter cell have? ___
In mitosis, how many chromosomes does each daughter cell have? ___
In mitosis, how many chromosomes does each daughter cell have? ___
Are gametes, or sex cells, identical to each other or different? _________________
Are gametes, or sex cells, identical to each other or different? _________________
Are somatic cells, or body cells, identical to each other or different? ___________________
Are somatic cells, or body cells, identical to each other or different? ___________________
Skill 1: Which kind of cells use mitosis to divide?
Skill 1: Which kind of cells use mitosis to divide?
What are two names for the type of cells which use mitosis to divide?
What are two names for the type of cells which use mitosis to divide?
Body cells, also called somatic cells, use mitosis to divide.
Body cells, also called somatic cells, use mitosis to divide.
Skill 2: In mitosis are the daughter cells identical or different from the original cell?
Skill 2: In mitosis are the daughter cells identical or different from the original cell?
If you compare the number of chromosomes in the original cell to the number of chromosomes in each of the new daughter cells, what do you know?
If you compare the number of chromosomes in the original cell to the number of chromosomes in each of the new daughter cells, what do you know?
This process results in identical cells. One skin cell is exactly like the others around it, including the one it came from. Each cell has 46 chromosomes and are exactly alike.
This process results in identical cells. One skin cell is exactly like the others around it, including the one it came from. Each cell has 46 chromosomes and are exactly alike.
Skill 3: What are the stages of the cell cycle, in order, and what happens in each stage?
Skill 3: What are the stages of the cell cycle, in order, and what happens in each stage?
A cycle is a scientific word for circle, meaning that it goes around and around without stopping. There are four main parts of the cell cycle.
A cycle is a scientific word for circle, meaning that it goes around and around without stopping. There are four main parts of the cell cycle.
Interphase - the cell is not dividing. It is doing its job. If it is a muscle cell, it helps with movement. If it is a brain cell, it sends messages to other cells. If it is a cell in the eye, it helps the organism to see. Interphase has 3 parts.
Interphase - the cell is not dividing. It is doing its job. If it is a muscle cell, it helps with movement. If it is a brain cell, it sends messages to other cells. If it is a cell in the eye, it helps the organism to see. Interphase has 3 parts.
G1 - remember 'growth' - right after the cell divides in two, each daughter cell starts growing during G1.
G1 - remember 'growth' - right after the cell divides in two, each daughter cell starts growing during G1.
S - remember 'synthesis' - the cell has to synthesize, or make, a new copy of DNA. When the cell divides again, it will have one copy for each new cell.
S - remember 'synthesis' - the cell has to synthesize, or make, a new copy of DNA. When the cell divides again, it will have one copy for each new cell.
G2 - remember 'getting ready to divide' - the cell makes extra copies of organelles before it enters mitosis, to divide once more.
G2 - remember 'getting ready to divide' - the cell makes extra copies of organelles before it enters mitosis, to divide once more.
M - remember 'mitosis' - this is the part of the cell cycle where the cell divides. Mitosis is dividing the chromosomes in the nucleus. Cytokinesis is splitting up the cytoplasm and cell membrane.
M - remember 'mitosis' - this is the part of the cell cycle where the cell divides. Mitosis is dividing the chromosomes in the nucleus. Cytokinesis is splitting up the cytoplasm and cell membrane.
Time for G1 again!
Time for G1 again!
Skill 4 - Explain how meiosis is a 'reduction division' process and why that is necessary.
Skill 4 - Explain how meiosis is a 'reduction division' process and why that is necessary.
Skill 5 - Explain how sexual reproduction and crossing over contribute to genetic diversity. Why is this necessary?
Skill 5 - Explain how sexual reproduction and crossing over contribute to genetic diversity. Why is this necessary?
What's the points of having meiosis when we already have mitosis?
What's the points of having meiosis when we already have mitosis?
Meiosis produces haploid cells, those with half the usual number of chromosomes. This is important because, in sexual reproduction, the offspring receive half of their chromosomes from their mother and the other half from their father. When you combine the two halves, the baby has the right number of chromosomes again.
Meiosis produces haploid cells, those with half the usual number of chromosomes. This is important because, in sexual reproduction, the offspring receive half of their chromosomes from their mother and the other half from their father. When you combine the two halves, the baby has the right number of chromosomes again.
It is also important that sex cells are different. This is why you may share traits with your brothers and sisters, but you are not exactly the same. You only received half of your traits from your father and the rest from your mother. If all humans were genetically identical, we would all be susceptible to the same diseases and we would not have survival of the fittest, which helps the species survive over time. More about that during evolution...
It is also important that sex cells are different. This is why you may share traits with your brothers and sisters, but you are not exactly the same. You only received half of your traits from your father and the rest from your mother. If all humans were genetically identical, we would all be susceptible to the same diseases and we would not have survival of the fittest, which helps the species survive over time. More about that during evolution...
Genetically diverse populations are more likely to survive changing environments. Recombination of genes caused by sexual reproduction and crossing over, as well as mutations, provide for genetic diversity. Some new gene combinations have little effect, some can produce organisms that are better suited to their environments, and others can be deleterious, or negative.
Genetically diverse populations are more likely to survive changing environments. Recombination of genes caused by sexual reproduction and crossing over, as well as mutations, provide for genetic diversity. Some new gene combinations have little effect, some can produce organisms that are better suited to their environments, and others can be deleterious, or negative.
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