Unit 5 Biology Aqa

Topics: Action potential, Neuron, DNA Pages: 47 (11564 words) Published: May 16, 2013
Unit 5 Biology notes

Contents

Section 9.1 – Sensory Reception3
Section 9.2 – Nervous Control4
Section 9.3 – Control of heart rate5
Section 9.4 – Role of receptors6
Section 10.1 – Coordination8
Section 10.2 – Neurons10
Section 10.3 – The nerve impulse11
Section 10.5 – The speed of a nerve impulse12
Section 10.6/10.7 – Structure and function of the synapse / Transmission across a synapse13 Section 11.1 – Structure of skeletal muscle15
Section 11.2 - contraction of skeletal muscle17
Section 12.1 – Principle of homeostasis19
Section 12.2 - Thermoregulation20
Section 12.3/12/4 – Hormones and the regulations of blood glucose/Diabetes and its control22 Section 13.1 – The principles of feedback mechanisms24
Section 13.2 – The oestrous cycle25
Section 14.1 – Structure of ribonucleic acid26
Section 14.2 – Polypeptide synthesis – transcription and splicing27 Section 14.3 – Polypeptide synthesis – translation28
Section 14.4 – Gene mutation29
Section 15.1 – Totipotency and cells specialisation31
Section 15.2 – Regulation of transcription and translation32 Section 16.1 – Producing DNA fragments33
Section 16.2 – In vivo gene cloning – the use of vectors34 Section 16.3 – In vitro gene cloning – the polymerase chain reaction36 Section 16.4 – Use of recombinant DNA technology37
Section 16.5 - Gene therapy38
Section 16.6 – Locating and sequencing genes40
Section 16.7 - Screening for clinically important genes42
Section 16.8 – Genetic fingerprinting43

Section 9.1 – Sensory Reception

• A stimulus is a detectable change in the internal or external environment of an organism that produces a response. • The ability to respond to a stimulus increases an organism’s chances of survival. • Receptors transfer the energy of a stimulus into a form that can be processed by the organism and leads to a response. • The response is carried out by “effectors” which can include cells, tissues, organs and systems.

Taxis – A simple response that’s direction is determined by the direction of the stimulus

An organism can respond directly to a change in the environment by moving its body either:

1. Toward the stimulus (positive taxis)
2. Away from the stimulus (negative taxis)

Kinesis – Results in an increase of random movements

• Organism does not move towards/away from the stimulus • The more intense the stimulus the more rapid the movements • Kinesis is important when the stimulus is less directional such as heat or humidity

Tropism – a growth movement of part of a plant in response to a directional stimulus

Positive phototropism – shoots/leaves
Positive Geotropism – roots

Section 9.2 – Nervous Control

Nervous organisation

The nervous system can be thought of as having two main divisions:

1. The central nervous system (CNS) – brain and spinal cord 2. The peripheral nervous system (PNS) – Made up of pairs of nerves that originate either from the brain or the spinal cord

The peripheral nervous system

This is divided into:
• Sensory neurons which carry impulses away from receptors to the CNS • Motor neurons which carry nervous impulses from the CNS to effectors

The spinal cord is a column of nervous tissue

A reflex – involuntary response to a stimulus (you do stop to consider an alternative)

The pathway of neurons involved in a reflex is called a reflex arc.

Reflex arcs contain just 3 neurons:
1. A sensory neuron
2. An intermediate neuron
3. A motor neuron

There are several stages of a reflex arc:
1. Stimulus
2. Receptor
3. Sensory neuron
4. Synapse
5. Coordinator (intermediate neuron)
6. Synapse
7. Motor neuron
8. Effecter
9. Response

Importance of the...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Biology Study Guide
  • Unit 5 Biology Essay
  • Essay about level 5 unit 2
  • unit 520 level 5 Essay
  • Unit 5 7 arakin 5 course Essay
  • biology Essay
  • biology Essay
  • biology Research Paper

Become a StudyMode Member

Sign Up - It's Free