Topic 2 - Cells and Control(check)

cell cycle

series of events in which a cell grows, prepares for division, and divides to form two daughter cells

cell cycle checkpoints

G1, G2, M, S

What is colour blindness caused by?

faulty or absence of cone cells

What is short-sightedness(myopia)?

The ability to see close objects clearly; distant objects appear blurry

Mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

Interphase (Mitosis)

G1, S, and G2 phase of cell cycle

DNA is replicated in S phase(1 chromosome to 2 sister chromatids)

Stages of Mitosis

Prophase, Metaphase, Anaphase, Telophase (PMAT)

Prophase (mitosis)

Chromosomes become visible and form an x,centrosomes move to opposite sides of the cell nuclear membrane begins to fade, spindle fibres start to form

Metaphase (mitosis)

Chromosomes line up in the middle of the cell, nuclear membrane breaks apart, spindle fibres attach to the centromere of each chromosome

Anaphase (Mitosis)

cell elongates and sister chromatids are pulled apart toward the poles by the spindle fibres, each of the 2 sister chromatids that are a chromosome which have been pulled away from each other are now counted as an individual chromosome

Telophase and Cytokinesis

spindle apparatus disappears

chromosomes uncoil

cytoplasm and organelles separate so that each daughter cell has supplies to survive on its own (cytokinesis)

results in 2 identical daughter cells after the membranes come into contact(cytokinesis)

a protein wraps around the cell and begins to split the cell into two.Membranes(nuclei) form around the cytoplasm

Why is mitosis necessary?

for new cells, for growth and repair of body cells; duplicates of their parents (growth repair asexual reproduction)

Growth in animals

an increase in cell size and number

Differentiation

process in which stem cells become specialised in structure and function

What does differentiation allow?

the growth of mulyiple vital organs in an organism

The centromere is a region in which

sister chromatids are attached to one another in prophase

Centrosomes and Centrioles

form mitotic spindle; needed to form cilia and flagella, a centrosome contains 2 centrioles, centrosomes found at teh nucear envelope

Importance of mitosis

growth, repair, asexual reproduction

Asexual Reproduction

Production of genetically identical offspring without mating, ensuring survival in stable environments

Genetically Identical Cells

Result of mitosis where duplicated chromosomes ensure new cells are identical to the original

Cancer Growth

Uncontrolled cell division forming tumors that can spread, impacting overall health

Growth in Animals

Increase in cell number and size

What is the main function of muscle cells?

Shorten to cause movement of the body

How do muscle cells move the skeleton, heart, and internal organs?

By contracting and relaxing antagonistically in pairs

Structure-Function Relationship

Specific cell structures suited for functions, e.g., muscle cells' fibers for contraction

Cell Differentiation Importance

Critical for specialized cell development, ensuring efficient body functions

How to interpret percentile growth curves

1.Look at the percentile of height. It will depict an xth percentile etc

2.This means that the person is the same height or taller than x% of people in the data

3.This means that (100 - x)% of people are taller than said person

Example:A person in the 75th percentile will be taller than or the same height as 75% of people however 25% of people will be taller than said person.

Plant Growth Stages

Cell division, elongation, and differentiation stages in plant growth

storage cell(parenchyma)

cells filled with starch grains - they store it until it is needed for growth

Meristem

an area of cells(of a plant) that rapidly divide by mitosis.These cells are embryonic as long as the plant lives

zone of elongation

The zone of primary growth in plant roots where new cells elongate, sometimes up to ten times their original length.

zone of cell differentiation

the three tissues systems produced by primary growth complete their differentiation

Why is cell differentiation important?

Allows production of different tissues and organs that perform various vital functions in the human body.In plants, to be able to differentiate into cells such as palisade cells

Stem Cells

unspecialised cells that can differentiate into different cell types

Where are pluripotent stem cells found?

embryos

Pluripotent

Cells that are capable of developing into most, but not all, of the body's cell types

totipotent

Stem cells with the potential to differentiate into any type of cell.

Multipotent

cell with limited potential to develop into many types of differentiated cells

Where are totipotent stem cells found?

early embryo, usually the first 8-16 cells made

Where are multipotent stem cells found?

adult stem cells, they form as the organs form

Embryonic vs. Adult Stem Cells

Embryonic pluripotent cells vs. adult multipotent cells, differing in differentiation potential

Medical Applications of Stem Cells

Utilized in bone marrow transplants, regenerative medicine, and potential treatments for diseases

Benefits and Risks of Stem Cells

Potential for tissue repair with risks like tumor formation and ethical considerations

What is one ethical issue of stem cells?

As pluripotent stem cells are embryonic, some would argue that using stem cells prevents a new life

What are risks of using foreign stem cells?

Risk of rejection

Identify the brain parts corresponding to their colour and the arrow.

Orange - Front of brain

turquoise - cerebral cortex

pink - cerebellum, back of brain

beige - upper half, above the concave bit = medulla oblongata

arrow - spinal cord

What are the functions of the cerebral cortex?

most of the function and senses of the brain (taste, sight, personality etc.)

What is the main function of the cerebellum?

Movement and position and balance and coordination

medulla oblongata function

regulating vital function (breathing, digestion, heart rate)

connects brain to spinal cord

controls unconscious activities of the brain

spinal cord

carries electrical impulses from medulla oblongata to the rest of the body, part of the CNS

CNS (central nervous system)

brain and spinal cord

PNS (peripheral nervous system)

the sensory and motor neurons that connect the CNS to the rest of the body

What is the cerebral cortex split into?

2 hemispheres

What are the functions of the left cerebral hemisphere?

Verbal and other cognitive processes

What are the functions of the right cerebral hemisphere?

Perceiving world around us and creating images

How many separate areas or lobes does each cerebral hemisphere consist of?

Four

CT scanning

A computerized imaging technique that uses X-ray slices passed through the brain at various angles and then combined into an image

What is a tracer?

A radioactive molecule

Which form of brain scanning employs radioactive tracers?

PET scanning

How is a tracer made?

By using a cyclotron

What are the most commonly used tracers?

Radioactive glucose

Why do PET scans use tracers?

The tracer will decay to form a positron in the brain

When a positron meets an electron, gamma rays are emitted.

A computer can detect and locate these gamma rays.

What is the function of a PET scan?

To locate active brain areas, this is because more active brain areas take in more of the tracer.

What are spinal cord injuries?

Severe injuries to the spinal cord, such as vertebral fractures and dislocations

What is the result of spinal cord injuries?

Impairment of spinal cord function below the level of the injury

What are benefits of using CT and PET scanning together?

You can combine them to get an image of the brain with the active brain structures.

cerebellum damage causes

uncoordinated, jerky movements, loss of balance

medulla oblongata damage results in

respiratory failure, paralysis, heartbeat failure

cerebral cortex damage results in

loss of taste, smell, vision

Why is a brain tumour especially bad?

the cancer cells can spread throughout the body via the blood stream, furthermore parts of the brain can be affected from the tumour

Why is the brain risky to operate on?

Risk of infection

relatively hard to access

may be hard to obtain consent(the patient has brain issues), therefore potentially unethical

risks damaging healthy tissue

side effects

How can we study different functions of the brain?

By electrically stimulating different parts of the brain.

Explain why some types of spinal cord

damage cannot be fully repaired.

The CNS has limited regenerative ability.

Central Nervous System

Includes the brain and spinal cord, vital for processing sensory information.

Peripheral Nervous System

Comprises nerves outside the CNS, facilitating communication with the body.

How does the nervous system detect stimuli?

1.Stimulus

2.Sensory Neurone

3.Coordinator(Brain and Spinal Cord)

4.Motor Neurone

5.Response

How are sensory neurones structured?

Cell body in the middle of the cell, dendrites and axon terminals

Myelin Sheath

insulates dendrons + axons and speeds up electrical impulses

What is the pathway of an impulse in a sensory neuron?

Dendrites -> Dendrons -> Axons -> Axon terminal

What is the pathway of an impulse in a motor neuron?

Dendrites -> Axons -> Axon terminal

How are sensory neurones adapted?

myelin sheath for speed

long axon for faster transmission

label all parts of the eye

What is the cornea?

The clear tissue that covers the front of the eye

What are the functions of the cornea?

It is a protective and a refractive layer

What is an iris?

A ring of muscle tissue that forms the colored portion of the eye around the pupil

What is the function of the iris?

Controls the size of the pupil opening, thus the amount of light that enters the eye

pupil

opening in the centre of the iris through which light enters the eye

lens

Focuses light on the retina, muscles change the lens shape to cause fine focusing

What are cone cells?

Shorter retinal cells that operate best in bright light

What is the function of cone cells?

Enable high-acuity, color vision as they respond to different wavelengths

How many cone cells are there per human eye?

About 6 million

Where is the highest concentration of cone cells found in the eye?

At the centre of the retina (fovea)

How many types of cone cells are there?

3

What are rod cells?

Longer retinal cells that work best in dim light and enable you to see black, white, and shades of grey.

Where are rod cells located in the retina?

At the periphery/edges of the retina.

What is the visual acuity of rod cells?

Low visual acuity

How many rod cells are there?

about 120 million per human eye

What is the function of optic nerves?

Carries electrical neural impulses from the cones and rods to the brain

What is the composition of optic nerves?

Made of neurones

What is the Retina?

the light-sensitive inner surface of the eye