Caitlee Mead and Tess Coppedge
Investigation 2
Cells
Scientific Essay
Cells are important to anything and everything living. They have a very
complicated and hard working life cycle. There are many parts of cells, there is
cell respiration, cell reproduction, organelles, and how they make up organs. They
are very complex and make up anything and everything. Without cells you would
not be alive.
Cells have many parts and all of those parts have many functions. The Cell
Plasma Membrane controls entry into and out of the cell. It is a permeable
membrane surrounding cells and it chooses what enters and leaves the cell. The
cell wall shapes and supports the plant cell. Chlorophyll tap light and is used to
produce food for plants, the Chloroplasts is also used to make food for the plant.
The Chromosomes contain code which guides all the cells activity. Cytoplasm is a
jellylike substance within the cell. An Endoplasmic reticulum is the surface for
chemical activity. The Golgi Bodies stores and release chemicals. Lyosome is the
digestion center for the cell. Microtubule is a hollow cylinder that supports and
shapes the cell. Mitochondrion is a really important part of the cell because it is
the powerhouse for the cell. The nuclear membrane holds the nucleus together
and the nucleolus is the spherical body with the nucleus. The nucleus is where
chromosomes are found. The plastid stores food or contains pigment. Ribosomes
are where proteins are made and finally the vacuole contains water and dissolved
minerals. Vacuole is the cell’s storage or warehouse.
Chemical energy from food molecules is released and then partially
captured in the form of ATP is called Cell Respiration. Most commonly glucose is
used to examine reactions and pathways but carbohydrates, fats, and proteins
can also be used. In cell respiration there are three metabolic processes.
Glycolysis, Krebs cycle, and oxidative phosphorylation, each one happens in a
different region of the cell. Oxidative Phosporylation is in the electon
transportation chain and is carried throughout the inner mitochondrial
membrane. Glycolysis happens in the cytosol. Finally the Krebs cycle happens in
the matrix of the mitochondria. In the glycolysis is a six carbon surgar, glucose. It
is broken down into two molecules, a three carbon molecule called a pyruvate.
The change that happens is followed by a net gain of two ATP molecules and two
NADH molecules.
Cell reproduction is very important to living things. Different cells
reproduce in different ways though. Prokaryotes reproduce through binary
fissions. Mitosis and meiosis are the only two was that Eukaryotic cells
reproduce. Mitosis created two daughter cells with an equal number of
chromosomes. Meiosis creates four daughter cells, each of them have half the
chromosomes of the parent; they are used in sexual reproduction.
Organelles are a smaller part inside of cells. The three organelles inside of
the cells are Mitochondrion, Vacuole, and Chloroplasts. Mitochondria are
organelles that provide energy for the cell to be able to move, divide, and
contract. Basically they are the power centers for the whole cell. Mitochondria
are very small and they are different shapes, depending on what type of cell it is.
They have a double membrane just like the nucleus; mitochondria are membranebound organelles. The outer section of the membrane is smooth unlike the inside
of it. The inside is very complex considering it forms a fold called cristae. Cristaes
are things that increase the surface area. To create the energy that they do they
combine the sugar part of food with oxygen to produce ATP. A vacuole is a
membrane-bond sac that does the intracellular digestion and the release of
cellular waste products. In animals the vacuole is very small. In plant cells they
usually are large and help out with turgor pressure. Turgor is when a plant is wellwatered; then the water collects in cell vacuoles producing rigidity in the plant.
Without enough water, the pressure in the vacuole is reduced and the plant wilts.
Finally Chloroplasts are organelles found in all higher plant cells. The reason why
plants are green are because of chloroplasts, the chlorophyll which is what the
organelles contain. Chloroplasts also have a double a membrane, although they
are both outer. Within the stroma are other membrane structures - the thylakoids
and grana; this is where photosynthesis takes place.
Cells make up organs through what seems like a very difficult process. The
cells connect with other cells to make up the tissues. To make up organs the
tissues connect and function with other tissues. Cells interact with other cells and
something called an Extracellular Matrix, basically bond are sticks them together.
Cells also bind directly to other cells by desmosomes, hemidesmosomes, gap
junctions, and tight junctions. Desmosomes are where two cells bond together
through adhesion. This happens through a dense plate in each adjacent cell
separated by a thin layer of extracellular material. In atomy it is also called macula
adherents. Hemidesmosomes are structures similar to a desmosome; they join a
cell to its basilar membrane instead of to another cell. Gap junctions are where
protienaceous tubes connect to adjacent cells. These tubes let material pass from
one cell to another without having to pass through the plasma membranes of the
cells. Dissolved substances such as ions or glucose can pass through the gap
junctions. Large organelles such as mitochondria cannot pass. Tight Junctions are
intercellular junction made of a series of fusions of the junction membrane,
forming a continuous seal. It serves as a selective barrier to small molecules and
as a total barrier to large molecules.
As you can tell there are a lot of things that go into a cell to make it
function and live strong. There are also a lot of cells that go into a living thing to
make that live strong and function.