BIO 1201 PRACTICAL 2

photosynthesis equation

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.

cellular respiration equation

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP.

What are the two processes of photosynthesis

Light reaction and Calvin cycle

Where do light reactions take place?

thylakoid membrane

Light reaction process 

pigments in membranes absorb solar energy, releasing electrons down an electron transport chain → produces ATP by chemiosmosis → energy stored in NADPH→ photolysis splits water into e- and O2

Calvin cycle process 

ATP and NADPH generated in light reactions build CARBS, carbon fixation 

How is light absorbed in plants?

Carotenoids and Chlorophyll

Where is light absorbed in plants?

thylakoid membranes

What light is absorbed?

blue and red

why are leaves green?

the light spectrum is reflected by leaves 

blue/violet light

400 -450 nm

red light

650-700 nm

green to yellow light

500 -600 nm

Where do we measure oxygen release from?

photolysis, fixation of carbon dioxide to form carbohydrates, reducing power generated from ETC

Spectrophotometry

device that measures how much a chemical substance absorbs light by measuring the intensity of light as a beam of light passes through the sample solution 

Transmittance (t) formula

l(t) / l(o)

l(t) = light intensity before cuvette 

l(o) = light intensity after cuvette

Absorbance (A) formula

-log (l(t)/l(o))

Absorbance

amount of photons absorbed

beer lambert law 

A = E * c * l

A = absorbance 

E = molar coefficient/molar absorption

I = path length

c = concentration

Spectrophotometer range

UV :185-400 nm

Visible light: 400 -700 nm

True or False

Absorbance and O.D are the same units 

True 

Net photosynthesis

Gross photosynthesis and respiration

after 10 minutes, you record where the solution fell/rose on the pipette level

Gross photosynthesis equation

(net + cellular respiration)

• convert to hour

When is phenol red acidic and why?

it is yellow due to carbonic acid 

When is phenol red basic and why?

when it is red, CO2 is used up 

What is DPIP?

What does it mean when DPIP is blue?

oxidized

What does it mean when DPIP is clear?

reduced

• gains electrons, gets lighter in color 

DCMU

blocks electron flow from photosynthesis ll

Ammonia

eliminates H ion gradient, speeds up electron transport chain

Positive controls for photosynthesis lab

Tube 3 

Negative controls for photosynthesis lab 

tube 1 (dependent on chloroplasts)

tube 2 (needs light)

meiosis

How to find % of cells in each stage (cell divison)

Count the number of cells in each stage of meiosis and divide by the total number of cells examined, then multiply by 100 to get the percentage

multiply by 1440 minutes (24 hours)

What phase is the whitefish in?

anaphase

Sperm

ovary

crossing over frequency

nonrecombinant type ratio

4: 4

recombinant type ratio

2:2:2:2 or 2:4:2

relative distance (units)

½ * number of recombinant asci (%)

genome/plasmid

certain number of base pairs long

restriction endonucleases 

characterize and manipulate DNA molecules 

enzymes that recognize an specific sequence and cut the DNA at/near this site 

Palindromes

the sequence of the complementary strands read the same nucleotide sequence forward and backwards

sticky ends

overhanging single strand DNAresulting from the staggered cut made by restriction enzymes

mapping

characterizing the position of restriction endonuclease sites in a particular DNA molecule

plasmid

small, circular DNA molecule found in bacteria and yeast

agarose gel electrophoresis

charged DNA molecules migrate through a gel because they are placed in a powerful electricak field

PCR steps (D1S80 LOCUS)

1. set up the gel electrophoresis unit with 1% agarose gel

2. load 20 microliters of marker in one well

3. load 20 microliters of PCR sample in wells next to marker

4. fill all empty wells with 20 microliters water

5. run the unit for 10 minutes

Central Dogma

What are the x-values in a log graph?

distance in cm

what are the y-values in a log graph?

base pairs 

What does detergent do to cells?

destroys cell plasma membrane and nuclear envelope 

what does NaCl do cells/DNA?

blocks negative charges of DNA → pellets 

What should DNA purification look like?

white and stringy

What should DNA purification look like in water?

turn back into solution

(polar H20 molecules interact with various charges of the DNA)

mendelian genetics 

Gregor Mendel - 1866

Alleles

Gene governing an INHERITABLE CHARACTERISTICS occur in pairs/2’s

law of segregation

Alleles segregate in the production of Male and Female Gametes

law of independent assortment 

Alleles governing 1 inheritable characteristic segregate independently of alleles governing another characteristic

homozygous dominant

AA

heterozygous dominant

Aa

homozygous recessive 

aa

genotype

refers to an individual’s allele composition

phenotype 

refers to an individual’s PHYSICAL CHARACTERTISTIC

monohybrid cross

allows to cross a single pair of genes (1 trait crosses): between dominant and recessive phenotypes: RATIO of 3:1

dihybrid cross

allows two pairs of genes (2 trait crosses): between dominant and recessive phenotypes: RATIO of 9:3:3:1

homologous pairs

1 paternal and 1 maternal (meiosis (sex cells) vs mitosis (autosomal cells))

When do alleles separate in meiosis?

Anaphase l

sex linked traits

inheritance of a trait that is LOCATED ON A SEX CHROMOSOME

sex chromosome for male

XY

sex chromosome for female

XX

Drosophila flies

• easy to maintain 

• female = 800 eggs 

• 9-11 generation cycle in 11 days 

• 8 chromosomes 

• easily observable traits 

Chi squared formula

x² = E (observed value - expected value)²/expected value 

E = sum

Phenotypes of drosophila fly

body

• wildtype (+)

• ebony (e-)

• yellow (y-)

Eye

• wildtype (+)

• sepia (s-)

• white (w-)

• bar (b-)

wing 

• wildtype (+)

• dumpy (d-)

• vestigial (v-)

• wrinkled (r-)

• curly (c-)

central dogma

= DNA (replication) → Transcription into mRNA → Translated into Proteins

how are genes controlled?

epigenetic efforts, chemical modifications in the DNA, no changes in the DNA sequence 

identifying an individuals unique DNA sequence fingerprint

0.1% difference between all humans, 3 billion genome letters → DNA fingerprinting → identification of individuals → ancestry, diseases, paternity, etc.

polymorphic loci

sites of variation

polymerase chain reaction

amplification of DNA

DNA primers

short pieces of single-stranded DNA that are complementary to the template 

• forward and reverse 

three steps to PCR reaction

Denaturation: the samples are heated to 94-98 C for one minute to separate the template DNA into single strands 

Annealing: the samples are heated to 55-70 C for one minute to allow the primers to bind (anneal) to the template with their specific complementary sequences 

Extension: the samples are heated to 65-72 C for one minute to allow the DNA polymerase to build complementary DNA extending from each primer 3’OH

DNA fingerprinting using region VNTR D1S80

Chromosome 1 = D1S80 → variability caused by VNTR’s —> size of repeat of this D1S80 locus is around 16 bases pairs in length.

29 different alleles of D1S80 in humans, so there are 14-41 possible different repeats.

86% of the population is Heterozygous for this locus.

how to calculate number of repeats 

(PCR products size - base pairs)/ base pairs 

genotype frequency for a heterozygote

(allele frequency 1 x allele frequency 2 ) * 2

genotype frequency for a homozygote

(allele frequency)²

green genes

upregulated in NORMAL CELLS (downregulated in cancer cells)

red genes 

upregulated for CANCER cells (not in normal cells)

yellow genes

exhibit similar regulation in CANCER and NORMAL CELLS (=)

black genes

exhibit NO ACTIVITY/INACTIVE in both cell types