Topic 2

Define: Mitosis

Asexual process where two identical diploid data cells are produced.

What are the stages of the cell cycle?

Interphase, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis

What are the stages of the mitosis?

Prophase, Metaphase, Anaphase, Telophase

What is the first stage of the cell cycle?

Interphase

What is the second stage of the cell cycle?

Prophase

What is the third stage of the cell cycle?

Metaphase

What is the fourth stage of the cell cycle?

Anaphase

What is the fifth stage of the cell cycle?

Telophase

What is the final stage of the cell cycle?

Cytokinesis

What is the first stage of mitosis?

Prophase

What is the second stage of mitosis?

Metaphase

What is the third stage of mitosis?

Anaphase

What is the final stage of mitosis?

Telophase

Does mitosis begin with a diploid or haploid cell?

Diploid

What happens during interphase?

• DNA replication

• Protein synthesis

• Chromosomes form x shapes (2 armed)

What happens during prophase?

• Nucleus begins to break down

• Spindle fibres appear

• Chromosomes thicken/condense

What happens during metaphase?

Chromosomes lineup along the equator/ middle of the cell.

What happens during anaphase?

Chromosomes pull apart and move away to either end of the cell.

What happens during telophase?

Nuclei form at either the end of the cell.

What happens during cytokinesis?

2 genetically identical diploid daughter cells are produced.

Does mitosis produce diploid or haploid cells?

Diploid

Does mitosis produce genetically different or identical cells?

Genetically identical

Calculation: Mitotic Index

Number of cells in mitosis / total number of cells

Define: Binary fission

A type of asexual reproduction used by bacteria.

Explain how to calculate binary fission

1. Convert hours into minutes.

2. Total time / mean division time.

3. Use this answer and multiply 2 by itself this many times.

Define: Cancer

Non communicable disease where uncontrolled cell division by mitosis creates an abnormal cells know as tumours.

Define: Tumour

A lump formed of cancer cells.

What does uncontrolled cell division cause?

Tumours

Name 2 types of tumours

Benign and Malignant

Which type of tumour is cancerous?

Malignant

Which type of tumour is not cancerous?

Benign

Are benign tumours cancerous?

No

Are malignant tumours cancerous?

Yes

Which type of tumour is usually easy to remove?

Benign

Which type of tumour is usually difficult to remove?

Malignant

Are benign tumours usually easy to remove?

Yes

Are malignant tumours usually easy to remove?

No

Which type of tumour doesn’t spread/ invade other the parts of the body?

Benign

Which type of tumour spreads/ invades other the parts of the body?

Malignant

Do benign tumours spread?

No

Do malignant tumours spread?

Yes

Explain the process of malignant cells spreading

• Cells secrete chemicals.

• Stimulate blood vessels to grow.

• Cells detach.

• Spread via blood.

• Form new tumors called secondary tumors.

Define: Growth

An increase in size as a result of an increase in the number/size of cells due to mitosis.

How do cells increase in number or size?

Mitosis

What is the aim of percentile growth charts?

To check a baby is growing healthy.

How is growth measured for babies?

• Mass

• Length/Height

• Head circumference

What does it mean if a child is on the 90th percentile of a percentile growth chart representing height?

• This child is shorter than 10% of other kids their age but taller than 90%.

• In every 100 children, 90 would be shorter whilst 10 would be taller.

What does it mean if a child is on the 75th percentile of a percentile growth chart representing mass?

• This child is heavier than 75% of other kids their age but lighter than 25%.

• In every 100 children, 25 would be heavier whilst 75 would be lighter.

Define: Differentiation

When unspecialised cells like stem cells become specialised.

Define: Undifferentiated

Unspecialised cells that don’t have a function.

Define: Stem cells

Undifferentiated cells that differentiate into specialised cells.

What are embryonic stem cells?

Undifferentiated cells in an early embryo that differentiate into any type of specialised cells.

Are stem cells undifferentiated or differentiated?

Undifferentiated

Are specialised cells undifferentiated or differentiated?

Differentiated

Do stem cells have a function?

No

What do specialised cells have that stem cells do not?

A function.

What can stem cells differentiate into?

Specialised cells like heart muscle cells, red blood cells, nerve cells etc.

What do stem cells replace?

Replace damaged cells.

What do stem cells repair?

Repair damaged tissue.

Where are adult stem cells found?

Bone marrow

What can adult stem cells differentiate into?

Only major tissues/organ cells.

What can embryonic stem cells differentiate into?

Any specialised cell.

What are the benefits of using stem cells for medicine?

• Used to treat currently untreatable conditions.

• Used to grow organs for transplants.

• Used for medical research.

What are the risks of using stem cells for medicine?

• Rejection.

• Ethical issues around use of embryonic stem cells.

• Could be contaminated with pathogens.

• Stem cells divide quickly which could lead to cancer.

Where does cell division in plants occur?

Meristem

In which part of a plant root does mitosis take place?

Meristem

What is the meristem of plants?

An area of undifferentiated cells in a plant where cells are dividing rapidly by mitosis.

What is another name for the meristem?

Zone of cell division

What occurs in the zone of elongation?

Cells increase in length and contribute to plant growth.

What occurs in zone of differentiation?

Stem cells differentiate into specialised cells.

What is found at the end of shoots and roots to enable plants to keep growing?

Meristem

What does CNS stand for?

Central Nervous System

Define: Stimuli

A thing or event that leads to a reaction.

What do receptors detect?

Stimuli

Which type of cells detect stimuli?

Receptors

Where are the 5 receptors in the body?

Eyes, skin, ears, nose, tongue.

What stimuli do the eyes detect?

Light and color.

What stimuli do the ears detect?

Sound and vibrations.

What stimuli does the skin detect?

Pressure and pain.

What stimuli does the tongue detect?

Chemicals in food.

What stimuli does the nose detect?

Chemicals in the air.

What is the reflex arc?

An unconscious response to a stimulus that bypasses the brain. It includes 3 neurones.

Name the 3 types of neurone

Sensory, relay and motor.

What is the first neurone in the nervous system?

Sensory neurone.

What is the last neurone in the nervous system?

Motor neurone.

Describe the structure of sensory neurone

• Dendrites

• Dendron

• Cell body with nucelus

• Axon

• Axon terminals

• Myelin sheath

Describe the structure of relay neurone

• Dendrites

• Cell body with nucleus

• Axon

• Axon terminals

Describe the structure of motor neurone

• Dendrites

• Cell body with nucleus

• Axon

• Axon terminals

• Myelin sheath

What structures do all 3 neurones have?

• Dendrites

• Cell body with nucleus

• Axon

• Axon terminals

Which neurones have a myelin sheath?

Sensory + Motor

Which neurones have a dendron?

Sensory

Which neurone is connected to the effector?

Motor

Define: Effector

Muscle/gland

What is the Myelin sheath?

Fatty layer that insulate the neurone. This speeds up the electrical impulses transmission so less impulse is lost to the surroundings.

Does myelin sheath protect or insulate the neurone?

Insulate

Does the myelin sheath speed up or slow down the electrical impulse transmission?

Speed up

What is a gap between 2 neurones?

Synapse

What is a synapse?

A gap between 2 neurones; connects the neurones.

What happens in the synapse between neurones?

• The impulse reaches the axon terminals.

• A neurotransmitter diffuses across the gap.

• Next neurone detects this.

• New impulse is generates.

Explain the process of an electrical impulse in the reflex arc

• Receptors detect stimuli.

• Information converts into an electrical impulse.

• Impulse travels along sensory neurone, synapse, relay neurone, synapse, motor neurone and then the effector.

• This generates a response.