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LC Biology
LC Biology

The Heart

  • The heart is the pump of the circulatory system.
  • It is made of cardiac muscle which does not tire.
  • Cardiac muscle receives its own blood supply through the coronary arteries and veins.
  • The septum divides the heart into right and left sides.
  • The heart has four chambers; right atrium, right ventricle, left atrium, left ventricle.

Blood Flow Through the Heart

  1. The blood flows into the vena cava into the right atrium. It is deoxygenated blood.
  2. The valves open and allow the blood flow into the right ventricle. The valves close.
  3. The right ventricle contracts, valves open and blood is pushed... (More)
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LC Biology

All Biology Definitions for Leaving Cert

The Scientific Method

  • Scientific Method is a process of investigation where problems are identified and their explanations are tested by carrying out experiments.
  • Observation : An unbiased, accurate report of an event.
  • Hypothesis : An educated guess based on observations.
  • Experiment : An experiment is designed to test a hypothesis.
  • Data : Consists of measurements, observations/information gathered during an experiment.
  • Replicate : A repeat of an experiment.
  • Control : A comparison used to provide a standard against which the actual experiment can be judged.
  • Theory : A hypothesis that has been supported by different experiments.
  • Principle/Law : A theory that... (More)
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LC Biology

Biology: Viruses Q & A

2017

GIVE ONE EXAMPLE OF A BENEFICIAL VIRUS

Bacteriophages can be used to control bacterial infections

DESCRIBE HOW THE VIRUS REPLICATES

  1. Virus attaches to a host cell and inserts its nucleic acid into the cell cytoplasm.
  2. The viral enzyme destroys the host cell’s nucleus
  3. The virus uses host cell’s machinery to make more viral dna and protein coats
  4. New viruses are assembled and burst out of the host to infect other cells

DISCUSS THE STATEMENT “VIRUSES ARE NOT CONSIDERED TO BE LIVING”

Viruses have some features of living things, e.g. containing RNA or DNA, being able to replicate and having... (More)

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LC Biology

Biology - Variation & Evolution

Variation

Variation : differences amongst members of the same species. (E.g. hair colour/height)

Variation can be inherited (in genes) or acquired (learning over time E.g. ability to speak French)

Species

Inherited Variation amongst species occurs by two mechanisms:

1)Sexual reproduction: produces variation due to meiosis (see Chapter 13: The Cell Cycle)

2) Mutation: produces variation due to changes in the amount or structure of DNA.

Result: change in sequence of bases - no protein produced. Can affect a somatic cell (anc could cause cancer) or a gamete (and be passed onto offspring)

Mutations can occur spontaneously – for... (More)