One of the most important aspects to life is the ability to reproduce. Species reproduction hinges on cellular reproduction. The ability for a cell to make copies of itself is an amazing process. It is happening on a constant basis all through your body and all through the living world.
In the human body, the 46 chromosomes form 23 pairs of chromosomes. The pairs form because the chromosomes are alike. When there are two of every chromosome the cell is called diploid. Sex cells, on the other hand, contain only one chromosome from each matched pair and are called haploid. Therefore, a human sex cell has 23 chromosomes, not 23 pairs of chromosomes.
Meiosis happens when an organism reproduces. Sex cells form with one half the chromosomes of the original cell. This way, when that cell pairs up with a sex cell from another organism, the result is a combination of chromosomes from both parents.
Mitosis is happening all the time throughout your body. In this process, the nucleus of a cell divides to form two identical nuclei. Each of the two nuclei contain the same number and type of chromosomes as the original.
Go to the website CellsAlive.com. On the left side of the website, there is a section called "interactive." Starting with the "Cell Model" link, go through each of the interactive activities (you don't need to do the puzzles or the quizzes). Make a comment (write a paragraph) about cell division based on what you learned through these demonstrations.
Hi everybody. I'm sorry I wasn't at school today. I hope you enjoyed the Planet Earth DVD . I think it's some of the most amazing footage of our world.
Adaptations are characteristics that an organism has that allow it to survive in it's environment. For example, the leopard can climb trees so that they can pounce on prey from above and sleep safely in it's branches.
Please comment on something interesting from the docementary today (linked). I would especially be interested in hearing about adaptations that you noticed in the living organisms discussed in the film.
We are approaching edible cell day, where you all will be bringing in models of eukaryotic cells made out of food we can eat. Do your best to find foods that will look similar to the actual organelles found in the cell. For example, ribosomes are small bead-like parts found on the rough endoplasmic reticulum. I think they look like Nerd candies.
Prizes will be awarded to best tasting, most accurate, and worst tasting.
Robert Hooke was one of the first to observe that all living organisms are made of structures which he called "cells." He named them after the living quarters for monks in a monastery (cells!). The word "cell," as defined by dictionary.com, is "any of various small compartments or bounded areas forming part of a whole." This definition works well for our understanding of what a cell is in life science. They are the simplest structures that make up life.
Watch the video about cells and answer the questions:
1. How many cells are in a human body?
2. Which parts of the body are made of cells?
3. What does the nucleus do inside the cell?
4. What does the membrane do?
5. Do cells communicate?
6. What other interesting thing did you learn from this video?