Cell (biology)

Parent Cells

A cell that's other cells' source, a cell dividing to produce 2 or more daughter cells or stem cell that's a progenitor of other cells or is the first in a line of developing cells.

Reproduction

All cells, including single-celled organisms, use cell division to reproduce.

Each time parent cells divide results in 2 new organisms. Each organism inherits very important informations and each new cell has a complete set of genetic information.

This reproduction is called "asexual reproduction" involving only 1 parent.

Offspring are exact genetic copies and have the same exact DNA as the parent. Multicellular organisms need to reproduce and pass their genetic info along to their offspring. Some multicellular can produce offspring by asexual reproduction.

Sexual reproduction: when 2 parents and produces offspring with genetically unique parents, since their cell have DNA from both parents.

This houseleek is repoducting asexually. Each rosette is an individual plant genetically identical to parent.

Growth

Most chemicals need to be dissolved in water to be used in chemical reactions in the cell.

Therefore it's important that cells contain alot of water and must get rid of carbon dioxide and other waste products.

Why does cell number increase as organism grows?

Chemicals used during cell activity and growth enter cell across the membrane and travel through cell to be used.

Movement of chemicals starts by diffusion.

Chemicals diffuse form area of higher concentration to area of lower concentration.

Water enters and leaves cells by process called osmosis in which water always move toward where solutio is more concentrated. Important chemicals must be available to all part of the cell, in the right amount of water, for the cell to function properly. Waste products must also diffuse out the cell quickly so they do not poison the cell. When cell is too large, chemicals and water can’t move through fast enough.

Repair

Our body sheds millions of dead skin cells per day, with all replaced by new ones.

Red blood cells are replaced around each 120 days.

If a bone break, cell divide to heal it. Each cut needs new cells to fill in gaps.

Diffusion: transport mechanism for moving chemicals in and out of cells, from area of higher concentration to area of lower concentration.
Concentration: substance’s amount (solute) present in a given volume is solution.
Osmosis: fluid’s movement usually water across a membrane toward an area of high solute concentration.

Gametes

Cells having half of DNA, unlike normal body cells. They are produced when parent undergo additional cell division process called meiosis,

Only 1 parent is there and young cells have exactly same DNA as parent.

When 2 gametes combine, offsprings inherits characteristics from both parents.

What's a bacteria?

Free-living organisms often consist of 1 cell
Among first few life form appearing Earth

Prokaryotes

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Prokaryotes are type of cell that lack a nucleus and nuclei

and other membrane-bound organelles:

Mitochondria
Endoplasmic reticulum
Chloroplasts
Lysosomes

These cells are typically smaller and simpler in structure than eukaryotic cells, which do have a nucleus and other membrane-bound organelles. Prokaryotes are found in two main groups: bacteria and archaea.

Bacteria are the most well-known type of prokaryote. They are found in virtually every environment on Earth, from soil to water to the human body.

Some bacteria are beneficial to humans, such as those that live in the gut and help with digestion. Others can cause disease, such as Streptococcus pneumoniae, which causes pneumonia.

Advice to remember:

Prokaryotes don't need (lack) a nucleus because they are PRO

Beneficial: Favorable or advantageous; resulting in good.

What's a Eukaryotes?

Organisms with cells contains a nucleus and other membrane-bound organelles

Advice to remember:

The "Eu" in Eukaryote is a sound noobs make because they need nucleus, unlike Prokayotes who are pros.

Cell theory

All living things are made of cells
All cells have 3 things in common no matter what type
All basic unit of life
All come from pre-existing cells

Cell Complexity

There are 2 types of cells:

Plant Cell

Animal Cell

Cell Structure

Organelles are structures within a cell with specialized functions
Processes essential for life include:

Energy use
Movement/transportation of nutrients
Waste removal
Reproduction

What are cells?

Smallest unit that live on its own and makes up all living organisms and tissue of body.
Cells has 3 main parts:

Cell Membrane
Nucleus
Cytoplasm

All Cells have:

Cell Membrane: separates inside of cell from its environment
Cytoplasm
DNA, cell's genetic material

Genetic material: material carrying info and pass it down to next generation and again...

Organelles

Small structures in cell surrounded by membrane and each with specific job inside the cell.
But there are organelles that plant cells only have that animal cells don't, like chloroplasts.
Same thing for plant cells have organelles that plant cells don't, like centrioles.

Importance of cell division

1. Reproduction

Asexual

Offspring are genetically identical

Sexual

There is variation in offspring to parents

Cell Division's Importance

2. Repair and Replacement of damaged or dead cells.

3. Growth: increase in cell numbers causing growth, not increase in cell size

Cell Processes

Chemical and water needed by cell to carry life processes
What are those again?
Waste products need to be eliminated by cell
These needs are met by the 2 processes diffusion and osmosis

Diffusion

Diffusion = chemicals movements across the cell membrane from high concentration to area of low concentration

Simple terms: when dye is dropped in water, it spreads gradually until it's distributed everywhere in the container.

The dye gradully spreading is diffusion.

E.g. Axe spray in a change room

Osmosis

Cell Size

Diffusion and osmosis take time
Larger cell = longer process
Therefore smaller cell size = quicker, more efficient eliminating wastes, accumulation of necessary substances.

Similarities between Animal and Plant Cells

Cell Differences: Plant Cells | SparkNotes

Both have are eukaryotic cells and have membrane bound organelles, such as

Vacuole
Lysosome
Mitochondria
Endoplasmic Reticulum
Golgi Apparatus
Lysosomes
Peroxisomes

For none-membrane bound, both have

Cytoplasm
Cell Membrane
Nucleus
Mitro

Structurally, plant and animal cells = very similar, since they're both eukaryotic cells.
Both contain membrane-bound organelles like,
nucleus
Both also contain similar membranes, cytosol, and cytoskeletal elements.
However, few differences existing between plant and animals are very significant and reflect a difference in the functions of each cell.

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