Examining the processes of photosynthesis and cellular respiration

Autotrophs are producers that can make their own food from inorganic substances, using sunlight or other energy to fuel the reaction.

There are two main types of autotrophs:◦ Photoautotrophs- require photons from the sun

to carry out their oxidative reactions, cyanobacteria and plants are most famous

◦ Chemoautotrophs- do not require the sun to carry out their oxidative reactions, Bacteria that live in extreme conditions (sulfur

vents etc.)

Bacteria (prokaryotes – no nucleus) were first form of life on Earth.

Early Earth environment very extreme conditions.

Probably used inorganic molecules such as sulfur and iron compounds to fuel energy production through internal chemical reactions (metabolism).

In the struggle for survival (the winners reproduce most) efficient use of energy is vital.

Many complex organic molecules form from simpler molecules.

Cells that produce a molecule like chlorophyll that can harvest the sun’s energy provide a huge survival advantage.

Natural selection – organisms that have favorable traits in a particular environment are more likely to produce more offspring and pass on the favorable trait.

Photosynthetic organisms out compete chemosynthetic organisms at the Earth’s surface.

Waste oxygen produced by photosynthetic organisms (cyanobacteria) makes the Earth’s atmosphere poisonous to the chemosynthetic organisms.

This theory proposes that eukaryotic cells arose from symbiosis among several prokaryotic cells.

What evidence is there to support this idea?◦ Mitochondria and chloroplasts contain DNA that is

similar to bacterial DNA.◦ They also have ribosomes similar to bacterial

ribosomes◦ Like bacteria, mitochondria and chloroplasts

reproduce through binary fission, but eukaryotic cells divide by mitosis.

Changes in the contents of the atmosphere…

Changes in habitable places as the ability to photosynthesize became common-place

As conditions on the planet changed, populations needed to adapt in order to survive.

Adaptations are inherited character-istics that increase an organism’s chance of survival.

is a process involves CO2, H2O and sunlight as

reactants in a chemical reaction produces C6H12O6 and O2 as products. Where and how does this take place?

Use your textbook, pg 596 to label these parts…

• xylem

•Phloem

•Epidermis

•Palisade mesophyll

•Cuticle

•Stoma

•Spongy mesophyll

•Guard cells

Does this look familiar?

Working with your table partners, identify each cell part and summarize the function of each.

inside the chloroplast of a eukaryotic plant cell…◦ the structure of the chloroplast is

adapted in ways that facilitate the photosynthetic process,

◦ pigments in the chloroplast absorb and reflect different wavelengths of sunlight to make photosynthesis possible.

___ CO2 + ___ H2O Sunlight ___ C6H12O6 + ___ O2

(reactants) (products)

Can you balance the chemical equation?

Because sunlight is such an essential ingredient in this equation, cells have adapted structures that help to absorb the sunlight and use it to trigger the chemical reaction above…

Use the concept map to help you map the steps of this reaction-

Is the ability to photosynthesize an example of an adaptation?◦ If so, how?◦ If not, why not?

How does photosynthesis increase an autotroph’s chance of survival?

Amino acids -> polypeptides (precursors of proteins) -> coacervate molecules (clusters of macromolecules surrounded by a shell of water molecules) -> nucleic acids (self-replicating and subject to natural selection) -> lots more time…◦ Prokaryotic autotrophs

Lack an inner membrane around nucleus, small… ex: bacteria

◦ Eukaryotic autotrophs Have membrane organelles like chloroplasts…

ex: plants