Paper 1: Section 2- Cells and Control Flashcards
What are the differences between mitosis and meiosis?
Mitosis: Meiosis:
. Growth and . Gametes
repair
. Asexual . Reproduction
. 2 daughter cells . 4 daughter cells
. Diploid (46) . Haploid (23)
. Identical/ clones . Varied
What are the 6 stages of mitosis?
Interphase- DNA is copied
Prophase- the chromosomes pair up and the nucleus dissolves
Metaphase- chromosomes line up in the middle
Anaphase- spindle fibers pull chromosomes to the opposite sides
Telophase- a membrane forms around each set of chromosomes (2 separate nuclei)
Cytokinesis- two separate daughter cells form
What makes the stage of metaphase different in meiosis?
Dependant assortment
What is dependant assortment?
For any given pair lined in the center of the cell, there is one maternal chromosome and one paternal chromosome.
What is known as crossing over?
Segments of each chromosome, in a pair, attach themselves to the other.
What is the result of changes in the cell that lead to uncontrolled cell division?
Cancer
What happens to an unspecialised cell when it differentiates?
It becomes a specialised cell.
What is a tumour?
The lump of cells formed as a result of uncontrolled cell division.
A _______ tumour is not cancerous and cannot ______ to other areas of the body.
- benign
- spread
__________ tumours are fast-growing. They are _________ and can invade and spread to other areas of the ____.
- Malignant
- cancerous
- body
Describe the process called metastasis.
As the malignant tumour grows, cancer cells detach and can form secondary tumours in other parts of the body.
What are the chemicals and other agents that can cause cancer called?
Carcinogens
How do carcinogens cause cancer?
By damaging DNA, causing mutations to occur.
What is a mutation?
A random and spontaneous change in the structure of a gene, chromosome or number of chromosomes.
What is a common misconception about the growth of cancer?
A single mutation will not cause cancer. Several are required for this to occur.
List 5 lifestyle factors that are linked to cancer:
. Viruses like HPV
. The chemical carcinogens in cigarette smoke
. Alcohol intake
. Exposure to UV radiation, part of which is ionising,
. Fat and salt intake increases the risk of cancer
List 2 industrial and environmental factors that are linked to cancer:
. Exposure to ionising radiation increases the risk factor
. Exposure to chemical carcinogens
Name 7 specialised systems in animals.
- Circulatory system
- Excretory system
- Muscular system
- Nervous system
- Respiratory system
- Skeletal system
Name 5 specialised cells in plants.
- Palisade mesophyll
- Spongy mesophyll
- Guard cells
- Phloem Sieve tubes
- Xylem vessels
What is a zygote?
A fertilised egg cell.
What happens to an unspecialised cell when it differentiates?
It becomes a specialised cell.
What are the 3 following ways growth of babies are measured in?
- Mass (kg)
- Length (cm)
- Head circumference (cm)
What is a percentile growth chart?
A chart that is used to compare the growth of a baby to the growth of other babies.
What is an adult stem cell?
A type of stem cell found in specific locations in adults that can only differentiate into a limited number of related cell types.