Biology Exam 3

What kind of process is photosynthesis

Anabolic process(making something)

Light-Dependent Reactions

thylakoid reactions that occur in the photosynthetic tissues of the plants

Light-Independent Reactions

carbon fixation reactions/Calvin Cycle that build sugars

What are the properties of light?

• Light has waves(wavelength & frequency) and particles(photons)

• energy is dependent on wavelength

What wavelengths are included in sunlight?

All wavelengths

How do you see certain colors?

The light reflects the color you see, and absorbs the color you don’t see

Pigment

• any substance that absorbs light

• in plants it is chlorophyl

Accessory pigment

increase the range of light absorption

What happens when light strikes a pigment?

Light energy excites a pigment electron and boosts it into a higher orbital

Energy dissipation includes:

Florescence, resonance(energy transfer), and oxidation/reduction (gained or lost e-)

What are the redox properties of chlorophyll at the normal state?

poor oxidizing & reducing agent

What are the redox properties of chlorophyll at the excited state?(add light)

good reducing & oxidizing agent

Photosystems

protein complexes in the thylakoid membrane that captures and transfers light energy

Antennae Complex in light capture

array of pigments

Reaction Center in light capture

special pair of chlorophyll a that donates electrons

Electron Transport

photosystems utilize light energy to feed electrons to the electron transport chain

What happens in the electron transport chain?

• ATP & NADPH are generated

• NADP+ is the final electron acceptor, forming NADPH

• ATP is produced as H+ flows back down the concentration gradient through ATP synthase

Herbicides

kills plants

for example DCMU used in Vietnam and Paraquat that kills plants at their final stage

What is the first stage of the Calvin Cycle?

RuBP with 5 carbons uses the Rubisco enzyme with CO2 to make 6 carbon atoms and two phosphates

What is the second step of the Calvin Cycle?

make Phosphoglyceric acid(NOT USEFUL)

What is the third step in the Calvin Cycle?

reduction phase where it generates energy making ADP & NAD+

What is the fourth step in the Calvin Cycle?

Make Glyceraldehyde 3-Phosphate (VERY USEFUL) and 1 molecule of G3P makes whatever plant needs (sugar mainly)

What is the fifth step in the Calvin Cycle?

regeneration phase where we use more ATP energy to make 5G3P and start the whole process again

Why is the Rubisco enzyme trouble?

1. can make the plant too hot causing its stomata to close in order to preserve water, trapped in O2 leaves

2. causes a reaction with CO2 and RuBP making it go through photorespiration

Photorespiration

• does not produce any usable sugar

• produces toxic ammonia

• incurs direct cost of 2ATP and 1NADPH

• net loss of carbon

How do you control Rubsicos activity?

C4, C3, and CAM

Process of C4

Taking Xylem in the middle, surrounded by little Phloem, surrounded by bundle sheath cells creating a vascular bundle

What does CAM do at night?

capture CO2 and store it as malate (open stomata)

What does CAM do in the day?

malate releases CO2 for the Calvin Cycle (closed stomata)

C4, C3, CAM from least to greatest

C3, C4, CAM

How often do cells reproduce?

we lose about 30-50 thousand skin cells every minute

What are the 2 functions for cell division?

• growth or maintenance and repair of tissues (multicellular)

• reproduce (single-celled)

Eukaryotic cell cycle consists of:

• G1, S, G2, and Mitosis

How long is a human genome?

DNA from a single cell is 2 meters long

Genome

all the DNA an organism possesses

Genes

sections of DNA that are code for a particular protein

chromosome

a piece of DNA and proteins tightly wound together and helps organize the DNA

How many chromosomes to humans(somatic) have?

46 chromosomes

Karyotype

diagram or picture of chromosomes

How many pairs of chromosomes to males and females have

• females: 23 homologous pairs

• males: 22 homologous pairs and 1 heterologous pair

Diploid

2n and 46 chromosomes

Haploid

1n and have 23 chromosomes

Which chromosome pairs are not homologous?

males because of their XY chromosomes

During what phase do the chromosomes replicate?

S-Phase

A replicated chromosome consists of the two copies of _______?

sister chromatids

What is the middle of a chromosome called where they are attached?

centromere

microtubules

important for lining up, moving , and separating replicated chromosomes to form the mitotic spindle with the centrioles

What happens during Prophase of Mitosis?

• the replicated form of chromosomes condense in the broken down nuclear membrane

• mitotic spindle starts to form

What happens during Metaphase of Mitosis?

the mitotic spindle attaches to each side of the chromosomes in the center

What happens during Anaphase of Mitosis?

the sister chromatids are separated

What happens during Telophase/Cytokinesis in Mitosis?

• reformation of the nuclear membrane

• cell division

At completion of Mitosis:

each daughter cell is fully formed and reenters Interphase or go to G2 phase

What happened if the cell becomes quiescent(exits cell cycle)?

• may be temporary or permanent

• cardiac muscles

• nerve cells

What can trigger cell division outside the cell?

• horomones

• injury

• crowded

What are the 3 checkpoints that internally regulate cell division?

G1, G2, M

What does the G1 phase do?

determines whether conditions in the cell are favorable for division

What are the 3 things that the G1 phase checks for?

• growth factors (horomones)

• check for DNA damage

• adequate number of resources to complete division

What does the G2 phase do in division?

prevents entry into the mitotic phase if certain conditions are not met by making sure chromosomes are replicated and not damaged

What does the M phase do?

checks to make sure the sister chromatids are correctly attached to the mitotic spindle

What would happen in the M phase if the sister chromatids were not properly attached to the spindle?

it would cause mutations with the daughter cells

How does down syndrome happen?

when there is an extra 21st chromosome copy in the daughter cells

What is cancer?

occasionally replication errors occur and slip past the checkpoints

oncogene

genes that cause a cell to become cancerous

What is Meiosis?

process of cell division that generate haploid gametes for sexual reproduction

Sperm + Egg =

zygote

Where are plant sperm and eggs created in the plant

in the ovaries and anthers

How many chromosomes do humans have?

46 chromosomes

All maternal and paternal chromosomes have the same structure, size, and genes besides ______?

sex chromosomes

What are the two important things that happen in Meiosis?

• chromosome number is reduced by half

• genetic information is reshuffled

What happen in Interphase of Meiosis?

• DNA copies itself

• cell produces enzymes and proteins for division

What happens during the Prophase 1 of Meiosis?

chromosomes condense, pair, and cross over and recombination of genes

What is an allele?

an alternative form for gene

What happens during Metaphase 1 of Meiosis?

creates a double file alignment of homologous pairs, reduces chromosome number down to 23

What two things that occur in Meiosis generate genetic diversity?

• the crossing over of chromosomes in Prophase 1

• the double file alignment in Metaphase 1

What happens during Anaphase 1 of Meiosis?

daughter cells are split apart by the spindle

What happens during Telophase 1/Cytokinesis in Meiosis?

Homologous pairs split creating two cells

What is different about Meiosis 2?

it creates 4 haploid cells by splitting the daughter cells similar to Mitosis

Why are bananas triploid?

because they created an extra set of chromosomes and in Anaphase 1 they did not separate the haploid cells

What happens to when an organism has an odd number of chromosome sets

it become sterile (unable to reproduce)

Heredity

the transmission of traits from one generation to the next

What did Gregor Mendel do?

• discovered some primary principle of inheritance with pea pods

• studied individuals traits in large well controlled environments

• discovered discontinuous variation

What did Mendel discover?

• offspring are a blend of parents traits

• traits exhibit continuous variation

What are the Mandelien crosses?

established true-breeding of individuals and mating with different individuals made hybrids

What is a character?

a heritable feature that varies among individuals

What is a trait?

a variant of a character that results from different alleles

Homozygous

individual possesses 2 identical alleles (true-breeding)

Heterozygous

individual possesses two different alleles

Phenotype

the physical expression of an allele combination

Genotype

the allele combo possessed by one individual

Mendel’s method consists of what 3 generations?

P, F1, F2

What happens during P-Parental generation?

true breeding parents with different traits were crossed to produce the F1 generation

What happens during the F1 generation?

resulted from P generation and then self-fertilizes to produce the F2

Dominant allele

allele is expressed over the other alleles

Recessive allele

has no noticeable affect on appearance (latent)

Punnett Squares

only predict expected possibilities of offspring genotypes, not the actual

Test cross

used to determine whether an individual expressing the dominant trait is homozygous or heterozygous by crossing the unknown individual with a recessive one

What are Mendel’s 3 Laws?

1. Law of Segregation

2. Law of Independent Assortment

3. Law of Dominance

Law of Segregation

alleles segregate during Meiosis, offspring receive one allele from each parent (True)

Law of Independent Assortment

genes are inherited independently of each other (true if not linked)

Law of Dominance

recessive alleles are always masked by dominant alleles ( true if completely dominant)