2.1.1 Outline cell theory.

Three main principles of cell theory:

            -all organisms are composed of one or more cells

            -cells are the smallest units of life

            -all cells come from pre-existing cells

2.1.2 Discuss the evidence of the cell theory.

-Humans have not been able to find any living entity that is not made of at least one cell.

-After sterilizing chicken broth by boiling, Louis Pasteur showed that living organisms would not ‘spontaneously’ reappear. Only after exposure to pre-existing cells was life able to re-establish itself in the sterilized chicken broth.

-By looking through a microscope, Robert Hooke first described cells in 1665 while observing cork. Other scientists after him had made similar statements about cells. 

2.1.3 State that unicellular organisms carry out all the functions of life.

Unicellular organisms carry out all the functions of life. 

2.1.4 Compare the relative sizes of molecules, cell membrane thickness, viruses, bacteria, organelles and cells, using the appropriate SI unit.

-A molecule = 1 nm
-Thickness of cell membrane = 10 nm
-Viruses = 100 nm
-Bacteria = 1μm
-Organelles = up to 10 μm
-Eukaryotic cells = up to 100 μm

2.1.5 Calculate the linear magnification of drawings and the actual size of specimens in images known as magnification. (use an example or explain how to)

How To:

            1.Take a measurement of the drawing (width or length)

            2.Take same measurement of the specimen

            3.Convert units if needed

            4.Place your values into the equation

            5.Magnification=length of drawing/length of actual specimen

            *You can also calculate the length of the specimen if it is unknown: length of the                   drawing/magnification

2.1.6 Explain the importance of the surface area to volume ratio as a factor limiting cell size.

Substances need to be taken into the cell to fuel the many reactions that occur within the cell and waste products need to be taken out. When the cell increases in size, so does its chemical activity, so more substances need to be taken in and removed. The surface area affects the rate at which particles can enter and exit the cell. Volume affects the rate at which materials are made or used within the cell, hence the chemical activity per unit of time. As the volume of the cell increases, so does its surface area. However, when the cell gets bigger its surface area to volume ratio gets smaller. If the surface area to volume ratio gets too small, the substances won’t be able to enter the cell fast enough to fuel the reactions and waste products will build up. The cell will also not be able to lose heat fast enough, so it may overheat. 

2.1.7 State that multicellular organisms show emergent properties.

Multicellular organisms show emergent properties. 

2.1.8 Explain that cells in multicellular organisms differentiate to carry out specialized functions by expressing some of their genes but not others.

Every cell in a multicellular organism contains all the genes of that organism. However, different genes are activated depending on the cell. This is why we different cells make up different parts of our body. Cells can develop in different ways, which is called differentiation. Differentiation depends on gene expression which is regulated mostly during transcription. It is an advantage for multicellular organisms as cells can differentiate to be more efficient. On the other hand, unicellular organisms have to carry out all of the functions within one cell.

2.1.9 State that stem cells retain the capacity to divide and have the ability to differentiate along different pathways.

Stem cells retain the capacity to divide and have the ability to differentiate along different pathways.

2.1.10 Outline one therapeutic use of stem cells.

A bone marrow transplant is one therapeutic use of stem cells. Stems cells in bone marrow give rise to red blood cells, white blood cells, and platelets, so they can be used to treat patients with cancer. When a patient goes through chemotherapy, it kills both the cancerous cells and the healthy cells in the bone marrow. This prevents the patient from being able to produce blood cells. Before the patient is treated with chemotherapy, he or she can undergo a bone marrow harvest in which stem cells are removed from the bone marrow by using a needle which is inserted into the pelvis. Stem cells can also be harvested from a matching donor. After the chemotherapy treatment the patient will have a bone marrow transplant in which the stem cells are transplanted back into the patient through a drip. These transplanted stem cells will then find their way back to the bone marrow and start to produce healthy blood cells in the patient. 

2.2.1 Draw and label (cell wall, plasma membrane, flagella/pili, ribosomes, DNA) a diagram of the ultrastructure of Esherichia coli (E. coli) as an example of a prokaryote.

2.2.2 Annotate the diagram from 2.2.1 with the functions of each named structure.

Cell wall: Protects the cell and also maintains a defined shape for the cell.

Plasma membrane: Semi-permeable membrane that controls the substances moving into and out of the cell. Substances are able to pass through it by either active or passive transport.

Cytoplasm: Contains many enzymes used to catalyze chemical reactions of metabolism and it also contains the DNA in a region called the nucleoid. Ribosomes are also found here.

Pili: Helps bacteria adhere to each other for exchange of genetic material.

Flagella (singular flagellum): It is made of the protein called flagellin. It helps bacteria move around by using a motor protein that spins the flagellum like a propeller.

Ribosomes: The site of protein synthesis. Ribosomes contribute to protein synthesis by translating messenger RNA.

Nucleoid: A region containing naked DNA which stores the hereditary material (genetic information) that controls the cell and will be passed to the daughter cells.

2.2.3 Identify structures from 2.2.1 in electron micrographs of E. coli.

2.2.4 State that prokaryotic cells divide by binary fission.

Prokaryotic cells divide by binary fission.

Binary fission (prokaryotic fission): A method used by all prokaryotes of asexual reproduction involving the splitting of the parent organism into two separate organisms.

2.3.1 Draw and label (ER, ribosome, lysosome, Golgi, nucleus, centrosomes, vacuole, mitochondria, plasma membrane) a diagram of the ultrastructure of a liver cell as an example of an animal cell.

2.3.2 Annotate the diagram from 2.3.1 with the functions of each named structure.

Ribosomes: Found floating free in the cytoplasm or attached to the surface of the rough endoplasmic reticulum and also in the mitochondria and chloroplast. They are the site of protein synthesis.

Rough endoplasmic reticulum: Can modify proteins to alter their function and/or destination. Synthesizes proteins to be excreted from the cell.

Lysosome: Contains digestive enzymes to hydrolyze macromolecules such as proteins and lipids into their monomers.

Golgi apparatus: Receives proteins from the rough endoplasmic reticulum and may further modify them. It also packages proteins before the protein is sent to it’s final destination which may be intracellular or extracellular.

Mitochondria: Is responsible for aerobic respiration. It converts chemical energy into ATP using oxygen.

Nucleus: Contains the chromosomes and therefore the hereditary material. The nucleus is responsible for controlling the cell.

Vacuole: They are for intracellular secretion, excretion, storage, and digestion.

Centrosomes: An area in the cell where microtubles are produced.

Plasma Membrane: Semi-permeable membrane that controls the substances moving into and out of the cell. Substances are able to pass through it by either active or passive transport.

2.3.3 Identify structures from 2.3.1 in electron micrographs of liver cells.

Vacuole

Ribosomes

Centrosomes

Plasma Membrane, ER, Mitochondria, Lysosome, Golgi Apparatus, Nucleus

2.3.4 Compare prokaryotic and eukaryotic cells.

In comparing prokaryote and eukaryotic cells I found that:

1. prokaryotes lack mitochdria but eukaryotes do not.
2. There are small ribosomes in prokaryotes but in eukaryotes there are larger ribosomes. 

3. In prokaryotes there are few or no organelles enclosed by a single membrance, in eukaryotes there are many organells. Some examples of them include the Golgi apparatus and the endoplasmic reticulum. 

2.3.5 State three differences between plant and animal cells.

There are several difference between plant and animal cells, here are three. 

1. It is unusual for animal cells to contain vacuoles, when they are present they are either small or temporary. Plants always have a large vacuole. 
2. There are no chloroplast in animal cells, but plants need chloroplast for photosynthesis. 
3. Plant cells are rounded and do not change shape because they have cell walls, animal cells can change their shape due to the lack of cell walls. 

2.3.6 Outline two roles of extracellular components.

The cell walls give the cell strength and helps it hold up to pressure. It is made up of cellulose in groups that called microfibris. This gives the cell its shape. Cell walls are found in plant cells.

Animal cells have glycoproteins in the extracellular matrix. Glycoproteins are for movements, support, and adhesion of the cell.