L6 6P

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A104 Biology Problem 6

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Presentation

Blocks of Life?

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In today’s problem…

You recognized that…

• All living things are made up of cells.

• Cells are the building blocks of humans, animals, plants.

• Organisms can be made of a single cell (unicellular) and many cells (multicellular)

What can you infer?

• There are differences in the cells between animals, humans and plants.

• The differences in these cells give different functions. • The overall function of the organism depends on the

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The approach

• What is the building block of life?

• What is the Cell Theory?

• How do cells differ between humans, animals and plants? What other types of cells are there?

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What is the building block of life?

• Cells are the basic unit of life and can be found in every living thing, including humans, animals,

plants and bacteria.

• Living things that are made of a single cell are

known as a unicellular organism, such as bacteria, while more complex organisms like humans,

animals and plants are multicellular organisms.

• Cells have general structures that allow it to be self-regulating, such as producing energy,

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What is the Cell Theory?

• All known living things are made up of one or more cells

• All living cells arise from pre-existing cells by division.

• The cell is the fundamental unit of structure and function in all living organisms.

• The activity of an organism depends on the total activity of

independent cells.

• Energy flow (metabolism and biochemistry) occurs within

cells.

• Cells contain DNA which is found specifically in the

chromosome and RNA found in the cell nucleus and cytoplasm.

• All cells are basically the same in chemical composition in

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How do cells differ between humans,

animals and plants? What other

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Cells

Prokaryotes

Bacteria Archaea*

Eukaryotes

Plant Animal

*Archaea are unique and unusual cells that are similar to bacteria but can live in extreme conditions

How do cells differ between humans,

animals and plants? What other

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Basic eukaryotic plant cell structure

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STRUCTURE FUNCTIONS

Cell Membrane Regulation of passage of materials into and out of the cell

Nucleus Contains most of the hereditary material (DNA) of the cell

Endoplasmic reticulum (Smooth and Rough)

Synthesis and intracellular storage and transport of materials such as proteins and steroids

Golgi Body Synthesis and secretion (often to the outside of the cell) of materials such as carbohydrates and proteins

Mitochondrion Derives chemical energy (in form of ATP) from organic materials for use by rest of cell (respiration)

Cytoskeleton Maintenance of cell shape (where there is no cell wall), formation of "tracks" along which organelles can run, and formation of the spindle during cell division

Ribosome Site of protein synthesis

Vacuoles Membrane bound organelle containing water, organic, inorganic molecules or enzymes

Cytoplasm The gel-like substance in the cell, 70% to 90% water, consisting of organelles, where most cellular reaction occur

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Eukaryotic Cells

• Can be subdivided into unicellular (single celled) or multicellular organisms. • Unicellular organisms

• Algae (eg. Chlorella), molds, protozoa

• Under the Kingdom Protista

• Multicellular organisms

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Prokaryotic Cells

• Compared to eukaryotic cells, they lack well-defined nuclei and

membrane-bound organelles,

• Single, circular chromosome only compared to

eukaryotes.

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Structures and its Function in a Prokaryotic

Cell

STRUCTURE FUNCTIONS

Cytoplasmic/Plasma

Membrane Regulation of passage of materials into and out of the cell

Cell Wall Protection and maintenance of cell shape

Capsule

Found in some bacterial cells, this additional outer covering protects the cell when it is engulfed by other organisms, assists in retaining moisture, and helps the cell adhere to surfaces and nutrients.

Nucleoid Contains most of the hereditary material (DNA) of the cell

Flagellum (Cilium) Provides motility, primarily for single-celled organisms. (Where an organism has more than 2 flagella, each is then known as a cilium)

Pili

- Hair-like structures on the surface of the cell that attach to other bacterial cells. Shorter pili called fimbriae help bacteria attach to surfaces.

Ribosome Site of protein synthesis

Cytoplasm The gel-like substance in the cell, 70% to 90% water, where most

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Main differences between

Eukaryotes and Prokaryotes

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Is it possible to build a living organism from

cells?

• Yes, theoretically it is possible!

• http://www.newscientist.com/article/dn2338 2-kidney-breakthrough-complete-labgrown-organ-works-in-rats.html#.VM7aadKUceI • The science is based on understanding

how cells grow, mature and function. • What do you think are some possible

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What have you learnt?

• What are cells, both prokaryotic and eukaryotic. • What is the Cell Theory and how it helps us

understand what makes up living things. • The basic structures and functions of the

organelles in cells.

• Such as the cell membrane, nucleus, mitochondria, cytoplasm

• Differences between eukaryotic (plant and animal) and prokaryotic cells.