Bio 110 Lecture Exam 4

pigments

pigments

critical to light reactions because they capture light energy

chlorophylls

pigments contained within photosystems

photosystems

located in the thylakoid membrane and trap light energy and use it to excite electrons

How is photon energy captured and where is it contained

captured by chlorophylls and contained in phtoosystems

How do photosystems work

photon energy is captured by atenna chlorophylls and radiated from one to another until it is captured at the reaction center chlorophyll, where electrons absorb the energy

What happens to energized electrons in photosystems

they leave the reaction center chlorophyll, are caputred by an electron carrier, and enter into an electron transport chain

How are electrons missing from the RCC replaced

if in PS2, water; if in PS1, PS2

How many photosystems are there in chloroplasts

2

Where does PS2 get replacement electrons from

water

Where do energized electrons from PS2 go

to the electron transport chain where they are carried to PS1

where does PS1 get replacement electrons froms

PS2

Where does the energy in the electrons that is lost at PS1 go

it is used to power a proton puimp to create a proton graident across the membrane

What channel do protons diffuse across the membrane through

ATP synthase

How does ATP synthase generate ATP

it uses the energy of the h+ flow

How is NADPH made in light reactions

photon energy re-energizes electrons in PS1, which are used to reduce NADP+

Similarities between PS1 and PS2

atenna chlorophylls capture photon energy which is used to energize within RCCs

What happens in PS2

electrons enter ETC, energy is used to produce ATP, replacement electrons come from water

What happens in PS1

replacement e come from PS2, re-energized with photon energy, reduce NADP+

linear electron flow

flow of electrons through the photosystems and other molecular components built into the thylakoid membrane

How many atp does the linear electron flow produce per NADPH

1.2

How many atp does the dark reactions use per NADPH

1.5

What can happen if electrons are not used to reduce NADP+ to NADPH

the re-energized electrons are transported back to the proton pump - cyclic electron flow

Why does CEF occur

to increase ATP production for use in dark reactions

Where do the dark reactions occur

in the stroma of the chloroplast

What are the inputs of the dark reaction

NADPH, ATP, and CO2

What are the 3 steps of the dark reactions

carbon fixation, reduction of pga, regeneration of RuBP

What happens in carbon fixation

RuBP and CO2 form a covalent bond to create a 6C intermediate, the 6C intermediate spontaneously breaks down into 2 3-C molecules -> PGA

What enzyme catalyzes carbon fixation

rubisco

What is RuBP

A 5-C sugar known as the carbon acceptor

What does the reduction of PGA require

NADPH as electron source, ATP as energy source

What is PGA reduced to

G3P

What are the 2 functions of G3P

used to make glucose, used to regenerate RuBP

What other synthesis pathways do the dark reactions feed into

other sugars, amino acids, lipids, nucleic acids

How much energy does glycose contain

686 kcal/mol

How do organisms extract energy from glucose

oxidation of glucose

What are the 2 phases of the oxidation of glucose

glycolysis and cellular respiration

Where does glycolysis occur

in the cytoplasm of the cells

What happens during glycolysis

glucose is converted into pyruvate

Where does cellular respiration occur

in the mitochondria of cells

What are the 3 steps of cellular respiration

oxidation of pyruvate, citric acid cycle, electron transport chain

What are the two ways ATP is generated during glycolysis and cellular respiration

the flow of protons through ATP synthase (chemiosmosis) and substrate level phosphorylation

Substrate level phosphorylation

enzyme takes a phosphate from one molecules and adds to ADP to create ATP

What are the inputs of glycolysis

1 glucose, 2 NAD+, 2 ADP

What are the outputs of glycolysis

2 pyruvates, 2 NADH, 2 ATP

What happens to pyruvate if oxygen is avaliable

cellular respiration - complete oxidation, produces h2o and co2

How many ATP are made and what efficiency does cellular respiration have

36, 38%

What is the max amount of ATP made from fermentation

2

What happens to pyruvate if oxygen is not present

fermentation - incomplete oxidation, produces organic products, produces NAD+

What does anerobic respiration in yeast produce

NAD+, ehtanol, co2

What is the purpose of anaerobic respiration

regenerate NAD+ to keep glycolysis going

What is produced with anaerobic respiration in muscle cells

NAD+ and lactate

What can happen with lactate molecules

they can be converted back into pyruvate (in cells) or converted back to glucose (by the liver)

Where does the oxidation of pyruvate happen

in the matrix of the mitochondria

What happens with the oxidation of pyruvate

1 pyruvate and coenzyme A is converted to Acetyl-CoA

What is the main point of the citric acid cycle

to cimplete the oxidation of the acetyl group

Where does the citric acid cycle occur

in the matrix of the mitochondria

Whaat are the 3 phases of the citric acid cycle

Acetyl and oxaloacetate and converted to citrate, the oxidation of the acetyl group is completed, oxaloacetate is regenerated

What are the inputs of the citric acid cycle

Acetyl group, NAD+, FAD, ADP, Oaloacetate

What are the outputs of the citric acid cycle

CO2, NADH, FADH2, ATP, oxaloacetate

What happens to NADH and FADH2

They transport electrons to the electron transport chain

What areas do the electron transport chain and chemiosmosis involve

the matrix, inner membrane, and intermembrane space

How many proton pumps does the mictochondria have

3 (1,2,3)

How does proton pump 1 get electrons

from NADH

How does proton pump 2 get electrons

FADH2

How does proton pump 3 (and 2) get electrons

electron transport chain

What is the final electron acceptor

oxygen

What powers the proton pumps

energy from the electrons

What do the proton pumps do

create a graident in the inner membrane space

How are protons involved in making ATP

they flow through ATP synthase which makes ATP

Why is the yield of cellular respiration less than 36 ATP

mitochondrial membranes leak some protons, proton graident is also used to drive other processess

Why do we need a method to catergorize and name organisms

allows scientists to communicate percisely, provides a method to show relationships between organisms

What do similar features allow us to in terms of relationships

group organisms together, infer common ancestry, infer how closely related organisms are

What are the two types of similarities in organisms

homology, analogy

homology

similrities due to a common ancestry

analogy

similarities due to a common type of solution to a survival problem

Which type of similarity is helpful for building family trees

homology

How are organisms named and catergorized

using hierarchial systems

Do higher or lower order groups contain more organisms

higher order

Linnaean system

groupings are based on observable physical charactersitics - kingdom to species

What was added to the Linnaean system

3 domains of life: bacteria, archaea, eukarya

Eukarya

organisms composed of one or more eukaryotic cells

What are the requirements for organisms to be part of Eukarya

have membrane bound nucleus, have many types of organelles composed on internal membranes, dna sequences of ribosomal protein and rRNA genes are unique

Similarities between archaea and bacteria

single celled, cell wall, have plasma membrane and riboosomes, lack a nucleus and internal membranes

Archaea

found in extreme environments, have biochemically unique plasma membrane, have unique cell wall structure, dna sequences of ribosomal protein and rRNA genes are unique

How does Archaea have unique plasma membrane structure

held together by ether bonds (more stable) not ester bonds, fatty acid chains are branched

How does Archaea have unique cell wall structure

composed on pseduopeptidoglycans and S-layer proteins

Bacteria

standard phospholipid membranes, cell wall of peptidogylcan, dna sequences of ribsomal protein and rRNA genes are unique

What are the four kingdoms of Eukarya

Plant, fungi, animal, and protists

Common features of animals

multicellular, lack cell wall, heterotrophs, obtain energy by consuming other organisms/structures made by other organisms

Common features of plants

obtain energy from sun, contain photo capturing pigments, autotrophic, have cell walls of cellulose

Common features of fungi

extract and absorb energy/carbon from surrdongins by secreting digestive enzymes, cell wall of chitin, reproduce by releasing spores

common feature of protists

only unifying feature is being eukaryotic

plant like protists

algae, giant kelp

animal like protists

amoebas, paramecium

fungi like protists

slime and water molds

mixotrophs

use a mix of different sources to obtain energy and carbon

Biological species concept

way to define a species, one or more populations of individuals that: interbreed under natural conditions, produce fertile offspring

What are the limitations to the biological species concept

fossil organisms (we don't know about their breeding), asexual organims, species that are geographically separated

Types of reproductive barriers

prezygotic and postzygotic

Prezygotic barriers

prevent formation of zygote - prevent mating or fertilization