In the week of 1/3-1/8

Green is definitions.

Blue is bullet points.

Red is everything else.

On Monday, Tuesday part of Wednesday of this week, people in our class presented their fermentation, protein synthesis, respiration and photosynthesis projects. Therefore, I cannot elaborate on anything I learned because I unfortunately didn't take notes of these presentations, though they were very good and informative.

This week, we started learning about Reproduction. I learned that:

Reproduction- The process of fertilization.

Fertilization- The process of the egg (ova) and the sperm joining.

We also made a chart about the following subjects:

• Organism Reproduction
• Cell Reproduction
• Sex vs. Reproduction

I unfortunately cannot make a chart, but I will clearly state the facts I know about each topic:

Organism Reproduction:

• In some, there is a sperm and egg to reproduce.
• In others, they split into two.
• The ones that split in two, they make a copy of the organelle and then replicate or copy the DNA.

Cell Reproduction:

• Before splitting, the cells must double in size.

Sex vs. Reproduction.

• Sex is like a cell delivery system.
• The sperm and egg join in sex.
• In both, they don't necessarily end up with a baby popping out.
• There is 50% sperm and 50% egg.

The next day, we talked more about reproduction.

We were asked:

Why do cells reproduce?

As a class, we came up with the two answers to this question.

We said:

• They reproduce to replace old and dead skin cells.
• They reproduce because we are growing.

We also learned that in plants, the roots are always reproducing.

We then started a lab about onion root tip cells and what they look like in the stages of reproduction. We thought of the following things to look for:

• Cells get bigger (larger cells)
• More DNA (bigger nucleus to get ready to accomadate for a new cell)
• More clumps of DNA (chromosomes.)
• More organelles.
• Splitting cells.

http://www.microscopy-uk.org.uk/micropolitan/botany/onion_root_mitosis.jpg

To see a picture of an onion root tip, click on the link above.

We drew pictures of the different looking onion root tips and what stages of reproduction we thought they were in.

For homework that night, we had to look up mitosis. Mitosis is:

Mitosis- When the nucleus divides into two nuclei and is part of a larger life cycle of life. It is in Eukaryotic cells. The Prokaryotic cell term for mitosis is Bianary Fission. The result is two identical cells.

On Friday, we looked at a stimulation and took notes about it, and we looked again at an onion root tip under a microscope.

I found notes about the following stages:

Interphase- When the DNA replicates and the centrioles divide.

Prophase- The first stage in mitosis (see above) when the nuclear envelope breaks down and strands of DNA form into chromosomes.

Prometaphase- When the nuclear envelope breaks down so there is no more recognizable nucleus.

Metaphase- Tension applied to the spindle fibers aligns and all of the chromosomes in one plane at the center of the cell.

Anaphase- When the spindle fibers shorten and the chromosomes are pulled apart.

Telophase- When the chromosomes reach the opposite poles of the dividing cell and the nuclei daughter cells form.

That is what I learned in science this week.