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Biology - Digestive System

Autor:   •  November 28, 2018  •  1,906 Words (8 Pages)  •  6 Views

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Atrium

The upper chamber that receives deoxygenated blood from the body and pumps it into the right ventricle.

Right Ventricle

The chamber of the heart that pumps deoxygenated blood to the lungs.

Pulmonary arteries

Blood vessels that bring blood back to the heart.

Pulmonary veins

Blood vessels bring oxygenated blood from the lungs back to the heart.

Left Atrium

The upper chamber that pumps oxygenated blood into the left ventricle.

Left Ventricle

The strongest chamber of the heart that pumps oxygenated blood to the entire body

Aorta

The largest artery in the body

Septum

The wall in the heart that separates the chambers

Red Blood Cells

Carries oxygen and carbon dioxide to form cells

White Blood Cells

Helps fight off infection

Platelets

Helps to clot blood

The Cell Cycle

Replication of chromosomes

Before replications, chromosomes have 1 chromatid

After they have 2 sister chromatids, held together at the centromere

Each chromatid has a copy of the same DNA

The growth stage: Interphase

Majority of the cell cycle

Cells grow and performs unusual functions

Number of organelles increase

DNA in the nucleus replicate

The division stage: Mitosis and Cytokinesis

One cell produces two new cells which have the same DNA

Mitosis

The continents of the nucleus separated into two identical copies

Has 4 phases: prophase, metaphase, anaphase and telophase

Cytokinesis

The cytoplasm and organelles divide into two separate cells

In animals cells, cell membrane pinches in

In plant cells, new cell wall made of cellulose forms between the 2 new cells

Why do cells need to divide

Tissue Repair

Millions of your body’s cells are injured or die every second

Remaining cells divide to replace them

Growth

cells need to divide in order for organisms to grow

Reproduction of the Organism

Asexual reproduction, one cell divides into two identical daughter cells

Sexual reproduction, cell division produces the sperm and egg, they combine to produce a new organism

Stages of Mitosis

Prophase

The chromosomes are condensed

Nuclear membrane disappears

Spindle fibers start to form, growing out of the centrosomes

Metaphase

Chromosomes line up at the equator of the cell

Chromosomes are attached to the spindle fibers by their centromere

Anaphase

The two identical chromatids split apart

The spindle fibers contract

Chromosomes are pulled to opposite poles of the cell

Telophase

Chromosomes are at the poles of the cell

Nuclear membrane reforms

Chromosomes begin to unpack into chromatin

Cells

4 Characteristics of Living Things

Obtain and use energy to power activities such as movement and growth

Try to maintain a constant internal environment

Reproduce

Made of cells

Cell Theory

All living things are made of one or more cells

The cell is the basic organizational unit of life

All cells come from pre-existing cells

Basic Types of Cells

Prokaryotic Cells

No true nucleus

Most are single celled organisms

Eg bacteria, algae

Eukaryotic

Has a true nucleus

Uni-celled or multi-celled organisms

Eg yeast (uni), plants and animals (multi)

Cell structure and functions

Nucleus

The largest organelle in a cell

It’s the control centre

Cell Membrane

Separates the inside of the cell from the external environment

Allows material to flow in and out the cell

Cytoplasm

The cytosol, organelles, and other life supporting materials such as sugar and water, all contained by the cell membrane.

Mitochondria

Supplies cells with energy

The

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