Cells And Controll

What is Mitosis?

Mitosis is a crucial process in the cell cycle that results in the division of a parent cell into two identical daughter cells. It consists of several stages: Interphase, Mitosis, and Cytokinesis, each with specific functions in cell division.

What are the stages of Mitosis?

Interphase is the preparatory phase where DNA is replicated and organelles are duplicated. Mitosis involves the alignment of chromosomes at the cell equator and their separation into two new nuclei. Cytokinesis is the final step where the cytoplasm divides, resulting in two separate cells.

Why is Mitosis Important?

Mitosis is essential for growth, tissue repair, and asexual reproduction.

What are Chromosomes?

Chromosomes are structures within the nucleus that contain DNA, which carries genetic information. Humans have 23 pairs of chromosomes (46 total), with one set inherited from each parent.

What are Gametes?

Gametes (sperm and egg cells) contain a haploid number of chromosomes (23), which combine during fertilization to form a diploid zygote.

What are Genes?

Each chromosome carries many genes, which are segments of DNA that code for proteins and influence traits. The diploid number is crucial for maintaining genetic stability across generations.

How does Growth occur in animals?

Growth in animals occurs through cell division (mitosis) and differentiation into specialized cells. Specialized cells, such as muscle and blood cells, have unique structures and functions adapted to their roles.

How does Growth occur in plants?

In plants, growth occurs through cell division, elongation, and differentiation, with many cells retaining the ability to differentiate throughout life. Plant growth is influenced by hormones like auxins, which regulate cell elongation and direction.

What is Differentiation?

Differentiation is the process by which unspecialized cells develop into specialized cells with distinct functions. In animals, differentiation typically occurs early in development, leading to specialized tissues and organs.

How does Cancer arise?

Cancer arises from mutations that lead to uncontrolled cell division, resulting in tumor formation. Tumors can be benign (non-cancerous) or malignant (cancerous), with malignant tumors capable of metastasizing.

What are Stem Cells?

Stem cells are undifferentiated cells capable of dividing and differentiating into various cell types. Embryonic stem cells can differentiate into any cell type and are derived from early-stage embryos.

What are Adult Stem Cells and Plant Meristems?

Adult stem cells, found in tissues like bone marrow, can form a limited range of cell types, primarily related to their tissue of origin. Plant meristems are regions of undifferentiated cells that can differentiate into any type of plant cell throughout the plant's life.

What is Therapeutic Cloning?

Therapeutic cloning involves creating an embryo with the same genetic material as a patient to harvest stem cells for treatment. This approach could potentially provide tissues or organs that are genetically compatible with the patient, reducing rejection risks.

What is the Central Nervous System (CNS)?

The Central Nervous System (CNS) consists of the brain and spinal cord, responsible for processing and transmitting information throughout the body. The brain is divided into several regions, each with specific functions, including the cerebral hemispheres, cerebellum, and brainstem.

What are the Cerebral Hemispheres?

The cerebral hemispheres are the largest part of the brain, comprising the cerebrum, which is responsible for higher brain functions such as consciousness, memory, and sensory processing. They are divided into left and right hemispheres, each controlling different functions and sides of the body.

What is the Cerebellum?

The cerebellum is located at the base of the brain and is crucial for coordinating voluntary movements and maintaining balance. It processes information from the sensory systems, spinal cord, and other parts of the brain to fine-tune motor activity.

What is the Medulla Oblongata?

The medulla oblongata is part of the brainstem and controls autonomic functions such as breathing, heart rate, and blood pressure. It acts as a relay center, transmitting signals between the brain and spinal cord.

What are CT and PET Scans?

CT (Computerized Tomography) scans use X-ray technology to create detailed images of the brain, useful for detecting bleeding and structural damage. PET (Positron Emission Tomography) scans involve injecting a radioactive tracer to visualize areas of high metabolic activity, often indicating tumors or other abnormalities.

What is the Nervous System?

The nervous system is responsible for coordinating actions and responses to stimuli, consisting of the central nervous system (CNS) and peripheral nervous system (PNS). Receptor cells detect stimuli and convert them into electrical impulses, which travel along sensory neurons to the CNS for processing.

What are Synapses?

Synapses are the junctions between neurons where neurotransmitters are released to transmit signals from one neuron to another. Different neurotransmitters can have varying effects on the speed and frequency of impulses in the receiving neuron.

What is the anatomy of the eye?

The eye is a complex organ that contains various structures adapted for light detection and image formation. The retina contains photoreceptor cells (rods and cones) that convert light into electrical signals for the brain to interpret.

What are common eye defects and treatments?

Common eye defects include myopia (short-sightedness) and hyperopia (long-sightedness), which result from improper focusing of light on the retina. Treatment options for refractive errors include glasses, contact lenses, laser eye surgery, and lens replacement surgery.

Mitosis & Cell Division

Mitosis is a type of cell division that produces genetically identical cells. It is used in growth, repair, and asexual reproduction. The stages of the cell cycle are interphase, mitosis, and cytokinesis.

Growth in Organisms

Growth in animals involves an increase in the number of cells (via mitosis). In plants, growth involves mitosis, elongation, and differentiation. Cell differentiation is important for specialised functions.

Stem Cells

Stem cells are undifferentiated cells that can become specialised. Embryonic stem cells can become any type of cell. Adult stem cells have limited differentiation (e.g. bone marrow). Meristems in plants can differentiate into any plant cell type. Stem cells are used in medicine for replacing damaged cells.

Cancer and Uncontrolled Mitosis

Cancer is the result of changes in cells that lead to uncontrolled cell division. Cancer cells divide continuously by mitosis, forming tumours.