Gen Bio 2 | Q3

Photosynthesis

Photosynthesis

the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar

Photoautotrophs

they produce their own food using light, water, carbon dioxide and other chemicals

Heterotrophs

Consumers, rely on the sugars produced by photosynthetic organisms for their energy needs

Chemoautotrophs

synthesizes sugar, not by using sunlight's energy, but by extracting energy from inorganic chemical compounds

Mesophyll

the ground tissue of a leaf, sandwiched between the upper and lower epidermis and specialized for photosynthesis

Stomata

small openings on the underside of a leaf through which oxygen and carbon dioxide can move

Chloroplasts

organelle found in plant and algae cells where photosynthesis occurs

Thylakoids

• A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy

• contains chlorophyll

Chlorophyll

Green pigment in plants that absorbs light energy used to carry out photosynthesis

Thylakoid lumen

fluid-filled interior space enclosed by the thylakoid membrane

Grana

A stack of thylakoids in a chloroplast

ATP

the energy currency of cells

F.F. Blackman

the first to suggest, in 1905, that enzymes must be involved in the reduction of carbon dioxide to a carbohydrate and that the process must consist of two separate sets of reactions

Light Reactions

only occur when solar energy is available (during daylight hours)

The Calvin Cycle

During this reaction, CO2 is taken up and then reduced to a carbohydrate that can later be converted to glucose.

Solar Energy

can be described in terms of its wavelength and its energy content

Absorption Spectrum

The pigments found in chloroplasts are capable of absorbing various portions of visible light

Carotenoids

are shades of yellow and orange, are able to absorb light in the violet-blue-green range

Photosystem

consists of a pigment complex and electron acceptor molecules within the thylakoid membrane

Noncyclic Pathway

During the light reactions, electrons usually, but not always, follow a pathway that begins with photosystem II

Electron Transport Chain (ETC)

a series of carriers that pass electrons from one to the other

Photosystem II

consists of a pigment complex and electron-acceptor molecules, receives electrons from water as water splits, releasing oxygen

Electron Transport Chain (ETC)

consisting of Pq (plasto-quinone) and cytochrome complexes, carries electrons from PS II to PS I via redox reactions. Pq also pumps H* from the stroma into the thylakoid space

Photosystem I

consists of a pigment complex and electron-acceptor molecules, is adjacent to NAD reductase, which reduces NADP* to NADPH

ATP Synthase Complex

has a channel and a protruding ATP synthase, is an enzyme that joins ADP +

Chemiosmosis

method of producing ATP because ATP production is tied to the establishment of an H+ gradient

The Calvin Cycle

a series of reactions that occur after the light reactions. It produces carbohydrate before returning to its starting point, ready to accept more carbon dioxide (CO,)

Melvin Calvin

the calvin cycle is named for?

Carbon Fixation

The first step of the Calvin cycle

RuBP carboxylase

• The enzyme that speeds the light-independent reaction

• a protein that makes up about 20-50% of the protein content in chloroplasts

3PG (3-phosphoglycerate)

The first 3-carbon molecule in the Calvin cycle is called

G3P

the product of the Calvin cycle that can be converted to other molecules a plant needs

Glucose Phosphate

can be combined with fructose and the phosphate removed) to form sucrose

sucrose

the molecule that plants use to transport carbohydrates from one part ot the plant to the other

Glucose Phosphate

the starting point for the synthesis of starch and cellulose

Starch

• Storage form of glucose

• Some are stored in chloroplasts but most are stored in amyloplasts in roots

Cellulose

a structural component of plant cell walls and becomes fiber in our diet because we are unable to digest it

Carbon Fixation

the process by which carbon dioxide is converted into more biologically useful organic compounds within living organisms

C3 Carbon Fixation

the most common of the three pathways

Photorespiration

Yields no sugars, produces ATP

Crassulacean Acid Metabolism (CAM Photosynthesis)

• these type of plants are adapted to extremely arid environments 

• Open their stomata only at night

• first discovered by plants called Crassulaceae

• evolved convergently several times in different plant clade

Crassulaceae

Family of flowering succulent (water-containing) plants that live in warm, dry regions of the world

Genetic Engineering

The direct modification of an organism’s genome

Genome

The list of specific traits (genes) stored in DNA

created the first genetically modified bacteria

History of GMO Development in 1973

created GM mice

History of GMO Development in 1974

first commercial development of GMOs (insulin-producing bacteria)

History of GMO Development in 1982

began to sell genetically modified food

History of GMO Development in 1994

began to sell GMOs as pets (Glofish)

History of GMO Development in 2003

GMO Process

All genetic changes affect the protein synthesis of the organism.

GMO Process

By changing which proteins are produced, genetic engineers can affect the overall traits of the organism

• Inserting new genetic material randomly or in targeted locations 

• Direct replacement of genes (recombination)

• Removal of genes 

• Mutation of existing genes

Genetic modification can be completed by:

Bacteria

the most common GMOs because their simple structure permits easy manipulation of their DNA

production of hydrocarbons

One of the most interesting uses for genetically modified bacteria is ____ which is usually only found in fossil fuels

Cyanobacteria, E. Coli

Examples of GMO Bacterias

Cyanobacteria

modified to produce plastic (polyethylene) and fuel (butanol) as byproducts of photosynthesis

E. Coli (Escherichia Coli)

This bacteria have been modified to produce diesel fuel

Genetically Modified Crops

• Bt corn

• Banana Vaccines

• Venomous Cabbage

Bt corn

•  One common modified crop

• A gene from the Bt bacteria is added so this produces a protein that is poisonous to certain insects but not humans

Bacillus Thuringiensis

what bacteria is added to bt corn

Banana Vaccines

Modified virus injected in sapling tree causes the bananas to contain virus proteins

Venomous Cabbage

Scorpion genes added to the cabbage prevent insects from eating it

• Insect resistant  

• Herbicide resistant  

• Drought/freeze resistant  

• Disease resistant  

• Higher yield  

• Faster growth  

• Improved nutrition  

• Longer shelf life

Other Reasons to Genetically Modify Crops

• Protein tracking  

• Disease detection

• Novelty pets 

Uses of Bioluminescent Animals

Genetically Modified Animals

• Fast-Growing Salmon

• Less Smelly Cows

• Web-Producing Goats

Fast-Growing Salmon

Genes from two other fish cause this salmon to continually produce growth hormones

Less Smelly Cows

Modifying bacteria responsible for methane production in cattle results in 25% less-flatulent cows

Web-Producing Goats

Spider genes in goats enable the production of spider silk in goat milk

• Risk to human health; unsafe to eat

• Harm to the environment and wildlife

• Increased pesticide and herbicide use

• Farmers’ health

• Seed and pollen drift

• Creation of herbicide-resistant superweeds

GMO Concerns