Zusammenfassung der Ressource
Biology Unit 2.1-Cells,Tissues and Organs
- Animal Cells and Plant Cells
- Animal
Cells
- Nucleus, Mitochondria, Cell Membrane, Cytoplasm, Ribosomes.
- Plant
Cells
- Nucleus, Mitochondria, Cell Membrane, Cytoplasm,
(Permanent vacuole), (Chloroplasts), Cell Wall, Ribosomes.
- Nucleus- controls all the activities of
the cell. They carry the instructions for
making new cells or new organisms.
- Cytoplasm- a liquid gel in which
most of the chemical reactions
needed for life take place.
- Cell Membrane- controls the
passage of substances into and out
of the cell.
- Mitochondria- structures in the
cytoplasm where oxygen is used and
most of the energy is release during
respiration
- Ribosomes- where protein synthesis
takes place. All of the proteins needed in
the cell are made here.
- Chloroplasts- absorb light energy to
make food my photosynthesis.
Found in the green chlorophyll.
- Cell Wall- made of cellulose that
strengthens the cell and gives it
support.
- Permanent Vacuole- a space in the
cytoplasm filled with cell sap. Keeps the
cell rigid
- Bacterial Cells
- Don't have a nucleus,
instead the genetic
material is suspended
in the cytoplasm.
- Extra DNA within the cell are called plasmids.
- Some bacteria have flagella, which are
long protein strands that propel it
forward.
- Yeast Cells
- Bigger than bacteria but still very small.
- Can respire aerobically and anaerobically.
- When yeast cells break down sugar in the absence
of oxygen, they produce ethanol and carbon dioxide.
This process is known as fermentation.
- Nucleus, Cell Wall, Cell Membrane, Cytoplasm.
- Specialised Cells
- Fat Cells
- Small amount of cytoplasm
and large amounts of fat.
- Few mitochondria as the
cell needs very little energy.
- They can expand up to 1000
times its original size.
- Cone Cells
- In the human eye, in the light
sensitive part, the retina.
- Outer Segment contains special
chemical which changes
chemically in coloured light.
- Middle segment is packed full
of mitochondria, which release
energy needed to reform the
pigment. This allows you to see
continually in colour.
- Final part is a specialised
synapse that connects to an optic
nerve. When coloured light
makes your visual pigment
change, an impulse is triggered.
The impulse crosses the synapse
and travels along the optic nerve
to your brain.
- Root Hair Cells
- Increase the surface area for water to move into the cell.
- Large permanent vacuole that speeds up the
movement of water by osmosis from the soil across the
root hair cell.
- Sperm Cell
- Long tail propels them forward.
- Middle section is full of
mitochondria which gives the
tail energy to work.
- Acrosome stores digestive
enzymes for breaking down the
outer layers of the egg.
- Large nucleus contains the
genetic information to be
passed on.
- Diffusion
- Is the movement of particles from an area of high concentration to
an area of low concentration.
- The bigger the difference, the steeper the concentration gradient.
- Surface Area:Volume effects the rate of diffusion. Cell membranes
or linings of organs that are folded have an increased surface area.
Therefore the rate of diffusion is greatly increased.
- Tissues and Organs
- A tissue is a group of cells with similar structure
and function working together.
- Muscular, Glandular, Epithelial, Epidermal,
Mesophyll, Xylem, Phloem.
- Organs are made up of tissues e.g stomach.
- Muscular tissue to churn the food and digestive juices of the stomach together.
- Glandular tissue to produce the digestive juices that break down the food.
- Epithelial tissue which covers the inside and outside of the organ.
- Organ Systems
- The Digestive System
- Is a muscular tube that squeezes your food through it. It starts at the
mouth and finishes at the anus. There are many different organs in
the digestive system, and there are glands such as the pancreas and
salivary glands. These produce and release digestive juices to break
down the food.
- The stomach and the small intestine are the main organs
where food is broken down and digested.
- Enzymes break down the large insoluble food molecules into smaller, soluble ones.
- The small intestine is also where the small, soluble molecules are absorbed into the blood. Once they
are there, they are transported in the blood stream around the body.
- The small intestine is adapted to have a very large surface area. this increase the rate of diffusion
from the gut to the blood.
- Plant Organs
- Have differentiated cells that form specialised tissues. (Mesophyll, xylem, phloem).
- Each organ carries out a specific job.
- Phloem transports dissolved food.
- Mesophyll tissue carries out photosynthesis.
- Xylem transports water and minerals.