Mrs. Aguirre

Ms. AguirreChapter 1

What are cells, and what do they do?

Cork Cells

Robert Hooke observed a thin slice of cork through microscope. The tiny walls reminded him of rooms, so he called them cells.Cells- Basic unit of structure and function of all living things

166518381839In 1665 Robert Hooke records his observations of cork cells. By 1838 Matthias determined that all plants are made up of cells. One year later Theodor concludes all animals are made of cells. Scientists have classified about a million types of plants and animals, and as different as they all seem to be, they are all made up of cells

Bacteria is made up of a single cell

However plants and animals are made up of many

Humans are made up of trillions

An organism with this many cells usually has different types of cells with many different functions.

The size and shape of a cell depend on its function

Red blood cells- disc shaped to fit through the smallest blood vessels.

Muscle cells are long and thin, and when they contract they produce movement

Nerve cells carry signals to the brain.

Plant cellsSome take in water from the soilSome protect the plantOther cells make food

Although cells are the basic unit, they contain an even smaller structures called organelles

All cells have similar organelles (except bacteria)

Cell membrane- thin covering that holds parts of the cell together

Nucleus and chromosomes

Nucleus controls the cells activities. One function is cell reproduction. Cells can only get so big so in order for plants to grow, the number of cells has to increase. Chromosomes

This is the characteristic of the cell.

When cells reproduce, the exact same chromosomes go into each new cell. Cytoplasm-Jelly substance

Contains many chemicals to keep the cell functioningCytoplasm contains mitochondria they release energy from food.

Vacuoles- store food, water, and waste materials 19Plant cell wall is more rigid so it has lots of strength

a plant also has chloroplasts which make food for the plant

Cell transportAll the activities of a cell require energy to function. This energy is supplied by the mitochondria.

Needs food, oxygen, and water to produce energy. How do cells get these materials and how do they get rid of material waste, like carbon dioxide?

Red blood cells

Red blood cells carry oxygen from the lungs to all parts of the body. So, oxygen diffuses out of red blood cellsBody cells

Theres a lot of carbon dioxide in body cells so they diffuse out into the blood. Cell membrane

Diffusion takes place through the cell membrane. It allows some particles to pass and it keeps out others.

Its like a filter.This movement of water and other dissolved materials is called osmosis

There is usually more water in the soil than in the roots of the plants, so water flows into the plant cells, fills the vacuoles, pushes the cytoplasm. This causes plants to stand straight up.On the other hand, when the soil is dry the plant has more water. Water begins to move out and the plant wilts and even dies.

Not all the materials a cell needs are small enough to get through through diffusion

Cells can use a carrier either to transport material that are too large or those that cant go through diffusion. Active transport- A carrier needs energy from a cell.

Cell energy pushes the carrier proteins through channels of the membrane Tissues, organs and systemsIn organisms made up of many cells, similar cells work together to perform a function. Together they form a tissue.

In most animals and humans there are four kinds of tissue

Muscle Tissue

Contract when they receive signals from the brain.

Made up of many cells

This contraction is what moves the skeleton.

Nervous tissue- brain, spinal cord, and places where you see, touch, taste, smell, and hear are all nervous tissue

Connective tissue

3rd kind of tissue-

In bones, cartilage and tendons

Blood is also connectiveEpithelial- includes the body covering of an animal. Lines most internal organs.

Tissues work together to form Organs

Skin is an organ.

It is made of many layers of epithelial, muscle, nervous, and connective. Each organ performs a major function that keeps the animal alive

The heart pumps blood through the rest of the body.

Organs work together to perform a function form a system

Plant cells also form tissues, such as the b ark of a tree

These tissues form organs such as the roots

The end of Ch1 Lesson 1

You will learn more about systems and plants coming up