Category: Year11 Science

Year11 NCEA Science

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Ionic bonding and Covalent bonding

Ionic bonding

Ionic bonding usually happens from reaction between metal and non-metal elements. You can see ionic bonding from a compound like NaCl (Sodium chloride). The forces of attraction between oppositely charged ions are called ionic bonds. As you can see in the diagram, Na+(Sodium ion) is a positive and Cl-(Chloride ion) is a negative ion. This is because sodium has lost one of its electron on it’s outer shell and chlorine has gained one electron from sodium element.

Sodium is an element but it becomes ion when it loses it’s electron from the outer shell. Chlorine is also an element – so it becomes negative ion as it gains a electron from the sodium.

An ionic bond (or electrovalent bond) is a type of chemical bond based on electrostatic forces between two oppositely-charged ions.

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Covalent bonding

Covalent bonds are forces that hold non-metal atoms together. The forces are formed when the atoms of a molecule share electrons.

As you may know, an atom is made of a tiny core called a nucleus, with tiny particles called electrons traveling about the nucleus. Sometimes when atoms come together, two electrons will start to travel about the nuclei of both atoms. The two atoms then share the pair of electrons.

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Bacteria

Functions of major parts

  • DNA: Contains genetic information for the bacteria. Controls all the chemical reactions within the cytoplasm.
  • Capsule: Protects bacteria from heat and chemicals
  • Flagellum: For movement.
  • Fimbriae/Pilli: For attachment (eg. on the surface of stomach)
  • Cell wall: Maintains the shape of the bacteria.
  • Ribosomes: For making protein.
  • Cytoplasm: This is where all the chemical reaction happens (including making proteins).
  • Plasma-membrane/ cell membrane: Controls what comes in and goes out.

Uses of Bacteria :

ref http://hubpages.com/hub/Uses-and-Classifications-of-Bacteria

  • A bacterium breaks down the organic fertilizer (decomposed vegetables and animal matter) into material that can be used by plants.
  • Some species of soil bacteria convert nitrogen into nitrites, compounds that are readily absorbed by plants.
  • Different commercial processes also need certain bacteria, like Anaerobic bacteria that ferment certain substances are used in the production of vinegar and some drugs, and in the aging process of cheeses.


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RNA and DNA

Our body is made up of very complex proteins. In fact, it is not just us that is made up of very complex proteins. It is more accurate to say that all the living things are made up of very complex proteins. There are two kinds to proteins – functional protein and structural protein. What is the difference? Well, the functional protein helps with the chemical reactions in our cells – but the structural protein is like what you can see with your eyes and touch. You can touch your skin, finger nail, hair, skin… and organs inside your body!

Why am I talking about these things?

Because I am about to let you know that your cells contain all the information about these proteins. The information is used to make and control every single things which are inside and outside your cell. It is like an encyclopedia, written in the language that our body understands. Where can we find the information then? The famous DNA – inside the nucleus of a cell.

The DNA is a long double helix molecule. Helix is the shape of a twisted ladder.

May be you have seen this picture before. The DNA is made up of thousands and millions of a single unit called NUCLEOTIDE.

Nucleotides have another name – Nucleic acid. This is because we often have to see things from chemistry perspective to understand their property as a molecule.

DNA and RNA is all made up of nucleic acids. But only difference is that DNA is like a ‘REFERENCE COPY’ book in the library. As you know these REFERENCE COPY books cannot be taken out side the library. So, what do you do when you need an information from the book? You would photocopy the pages you need wouldn’t you? The RNA is like the photocopied pages which can take information from DNA in the nucleus to the cytoplasm to make proteins. This is because making protein needs big chemical reaction and this reaction can only take place in the cytoplasm.

This is how RNA and DNA looks like. As you can see RNA is single stranded and DNA is doubles stranded. The part you cannot see is the difference in length. DNA is way way longer than RNA because it contains whole information, unlikely, RNA is way way shorter than DNA because RNA only contains copy of a section in a DNA strand.

You will actually more things about RNAs and DNAs when you take senior Biology subject. Hope this helps for you to kick start! :)

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Memorizing Periodic Table?

Hey, don’t hard out your self for learning the whole periodic table. Because you don’t need to. You are only expected to remember the first 30 elements on your periodic table. Your school will never ask you to remember the whole Periodic table and there is a big theory behind the Periodic table. It will be not even until Year11.

You will always get your periodic table during the test – BUT YOU NEED TO REMEMBER THE SYMBOL AND THE NAME of elements.

So, don’t learn their mass numbers of atomic numbers. It will be just a waste of time. When the time is right, you will get used to the properties of elements and understand why they have such placements.

But here is a tip for first 20 elements.

Harry He Like Beer Cold But Not Over Frothy. Nelly the Nanny Might Although Silly Punk She Climbs Around Kinky Cave.

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Structure of the heart

Functions of the heart structures

  • ATRIUM: smaller chamber of the heart through which blood enters the heart
  • VENTRICLE: larger chamber of the heart which pushes blood away from the heart
  • AORTA: major artery carrying blood away from the left ventricle
  • VENA CAVA: main vein returning blood to the right atrium
  • CORONARY ARTERIES: the first vessels to branch from the aorta; they supply blood to the heart muscle

Here is a really really good resource for your learning.

http://inspirahealth.com/templates/animations/heartanat.swf

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The coronary artery

THE CORONARY ARTERIES branch from the aorta as soon as it emerges from the heart. They deliver oxygenated blood the the heart muscle.

Coronary artery disease (or coronary heart disease) involves the build up of deposits in these crucial vessels. This reduces and sometimes completely blocks the flow of blood resulting in a heart attack.

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How does blood travel through the heart?

  1. deoxygenated blood returning from the body enters the heart through the superior vena cava and inferior vena cava.
  2. blood passes into the right atrium and right ventricle.
  3. right ventricle pushes the blood through the pulmonary arteries.
  4. blood passes through the lungs where it loses carbon dioxide and picks up oxygen.
  5. this oxygenated blood returns to the heart via the pulmonary veins.
  6. blood enters the left atrium and left ventricle.
  7. the left ventricle pushes the blood out through the main artery, the aorta.
  8. blood travels to all parts of the body where it delivers oxygen and picks up carbon dioxide.

Click to see this process in animation

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Space probe: Galileo

Galileo Mission to Jupiter

In December 1995, the probe that had been released by the Galileo spacecraft in July 1995 entered Jupiter’ atmosphere. Galileo had traveled 2.3 billion miles since its launch in October 1989. It spent the first 3 years in the inner solar system. During one flyby in Venus and two flybys of Earth, it gathered enough velocity from the gravity of the planets to reach Jupiter. Throughout its long journey, Galileo had been sending data about solar system back to Earth.

Galileo plunged into Jupiter’s crushing atmosphere on Sept. 21, 2003. The spacecraft was deliberately destroyed to protect one of its own discoveries – a possible ocean beneath the icy crust of the moon Europa.

Galileo changed the way we look at our solar system. The spacecraft was the first to fly past an asteroid and the first to discover a moon of an asteroid. It provided the only direct observations of a comet colliding with a planet.

Galileo was the first to measure Jupiter’s atmosphere.

You can find more info from http://solarsystem.nasa.gov/galileo/?CFID=29877228&CFTOKEN=25257562