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AU / Biology / BIO 1020 / meiosis tes

meiosis tes

meiosis tes


School: Auburn University
Department: Biology
Course: Principles of Biology
Professor: Zhong
Term: Fall 2015
Tags: Biology, Mitosis, meisos, and Genetics
Cost: 50
Name: Biology Test 3 Study Guide: ch 10-15
Description: This comprehensive study guide covers all of the information that will be on Tes #3. Chapters 10-15 are covered, which are photosynthesis, mitosis, meiosis, and genetics. I've used her notes and the textbook to completely explain all the necessary topics and included examples too!
Uploaded: 03/18/2018
6 Pages 6 Views 11 Unlocks

Dr. Sundermann Spring 2018

Photosynthesis is making energy from light.

BIOLOGY 1020 TEST 3: CH 10-15


Photosynthesis, Mitosis, Meiosis, Genetics (simple Mendeleian 1 and 2) A. “fully oxidized”: CO2. / fully reduced: C6H12O6

B. Mitosis occurs in diploid, makes identical cells for replacement and growth C. Meiosis takes a diploid and makes 4 different cells for genetic diversity  


Photosynthesis: making energy (endergonic) from light

i. reduction of CO2, oxidation of H2O,  

ii. plants grow by the intake of CO2 used to make cellulose (proven by Van  Helmont’s willow tree that “gained weight”)

iii. Structures for Photosynthesis

1. Leaf layers (inner to outer): mesophyll, two layers of bundle sheath cells  (calvin cycle in the top one), epidermis, stomata pores for ← CO2, O2→ 2. Chloroplasts: in every plant, but mainly in the mesophyll (tissue in the  interior of the lead- 30 chloroplasts each)

What is chloroplasts?

a. Outer membrane → Intermembrane space → Inner membrane

b. Stroma: dense fluid inside chloroplast

c. Granum: stack of thylakoids

i. Thylakoid: sac with chlorophyll pigment in thylakoid space  1. Chlorophyll A: key pigment, magnesium, bright green color

2. Chlorophyll B: accessory pigment, olive green color

3. Carotenoids: accessory pigment, yellow/ orange color

d. Electromagnetic Spectrum: wavelengths (short; high energy), visible  spectrum is used for photosynthesis  Don't forget about the age old question of How do winds blow around high and low pressure systems in the Northern Hemisphere?

i. Absorption Spectrum: wavelengths are absorbed/ not seen ii. Action Spectrum: photosynthesis can occur (violet-blue, red) 3. Photosystems: collection of 200-300 pigments embedded in the thylakoid membrane (one is the “reaction center” that raises with high energy e-) i. Light Harvesting complex: pigments and proteins, pass the  e- to the main rxn center

ii. Reaction center complex: proteins with chlorophyll a and a  primary electron acceptor: reducible (accepts e- molecule)

Fundamental laws of inheritance.

b. Photosystem 1: P680 chlorophyll a, very strong, oxidizes

c. Photosystem 2: P700 chlorophyll a, receives light as e 

B. Phase 1: “Light Reaction”/ “Z Scheme”/ “Non-cyclic Phosphorylation” in thylakoid i. Only occurs with sunlight and NADP available

ii. Goal: make ATP, NADH, and O2, (and electrons)

1. Photon from light hits Photosystem II (PSII), P680 reaction center,  high energy e- goes to Plastiquinone Q

a. PSII e- replaced by H2O photolysis (splitting water for e- and O2) 2. e- moves to cytochromes/ b-F complex (making ATP using a proton  gradient/ chemiosmosis broken by ATP synthase) and to plastocyanin 3. e- moves to plastocyanin and then Photosystem 1 (PSI), P700, which  raises its e- to a higher energy level when light hits it  If you want to learn more check out an organism able to form nutritional organic substances

4. e- move to primary electron acceptor and then Ferredoxin (Fd) and  reduce NADP to NADPH with “reductase”

a. Cyclic Phosphorylation: NADP not available, only PS1 happens and  Ferredoxin goes back to cytochromes. Produces ATP only

C. Phase 2: “Calvin Cycle”/ “Dark or Light Independent Reaction” in stroma

i. Requires ATP, NADPH, and CO2 from Phase 1 in thylakoid, can occur w/o light ii. Carbon Fixation: gaseous carbon into a solid structure, then into a sugar with e iii. Goal: reduce CO2 using NADPH and ATP to make sugar (PGAL) 1. RuBP (5 Carbon Ribulose Phosphate) gains a C from fully oxidized CO2 going through a rubisco enzyme (most abundant protein on Earth)- fixes  carbon into unstable 6 C molecule

2. Two 3 Carbon PGA molecules are phosphorylated (ATP used) to make  two 1, 3C biphosphoglycerate molecules

3. These are reduced (using NADPH) to make G3P/PGAL sugar (stores  potential energy) (6 formed for every 3 CO2, but only 1 is a product) 4. Some G3P/PGAL leaves and the rest stays in the cycle, and is phosphorylated to make RuBP

D. C3 vs C4 Plants

i. C3 Plants are the most common (ex: oats, wheat); low rate of photosynthesis in  the mesophyll cells and produce 3PGA (3C) using rubisco enzyme  1. CO2 enters mesophyll cells, Rubisco turns C in calvin cycle, produces 3PGA 2. On hot days, stomata cells close to prevent water loss, O2 builds up in leaf,  

confusing Rubisco which adds O2 to RuBP resulting in Photorespiration: O2 + RuBP → 3C and 2C molecule that doesn’t fit in calvin cycle, leaves  chloroplast to go to mitochondrion and get oxidized and self-destructedWe also discuss several other topics like all living organisms contain genetic material that is composed of


ii. C4 Plants (ex: corn, sugarcane, wheat); high rate of photosynthesis in bundle  sheath (around veins) and mesophyll cells (far from stomata) → produce  CoAA (4C) using PEP Carboxylase (better enzyme, more affinity to CO2 and  none for O2, will not fix carbon in CO2, found in mesophyll) and Rubisco in  bundle sheath cells too  

1. CO2 enters mesophyll cell where efficient PEP carboxylase adds CO2 to PEP  making 4C molecules exported through plasmodesmata to bundle sheath 2. In bundle sheath cells, CO2 is released and refixed by rubisco/ Calvin  Cycle, and makes pyruvate, sent to mesophyll cells and made into PEP by  ATP made by cyclic electron flow  

3. PEP accepts another C from CO2 and the reaction continues.  


A. Somatic Cells: all living cells except gametes (reproductive cells), i. Diploid Cells: 2n, mother cell, divides into two identical daughter cells 1. In Humans, 2n = 46 chromosomes

ii. Haploid Cells: n,  

B. Cell Cycle: the entire cell life

1. In Humans: 24 hours, Bacteria: 20 minutes

ii. INTERPHASE: G1, S, G2/ growth of a cell, prepares for division

1. G1: Growth of a cell in size, new organelles made  

a. time spent here varies the most among organisms

b. G0: Resting phase, cell stays and does not divide; nerve cells, liver cells c. Bone marrow cells are always dividing and never at G0 Don't forget about the age old question of smallest prokaryote

2. S: Synthesis of DNA, doubles its content

a. DNA packaged into chromosomes is replicated

b. Loose chromatin is condensed into a sister chromatid which doubles  and is held together by centromere making a chromosome  

3. G2: additional growth and making Tubulin (tube protein)

a. Centrioles replicate 

iii. MITOSIS: division of cell nucleus, cells entering have 4n chromosomes 1. Prophase: 4n

a. Nuclear membrane and nucleolus disappear 

b. Centrioles separate and form asters/ mitotic spindles

c. Chromosomes condense: Kinetochores assemble on centromeres (belt), act as attachment sites for future

2. Prometaphase

a. Nuclear envelope breaks


b. Microtubules attach to kinetochore 

3. Metaphase: 2n

a. chromosomes line up in the middle of the cell (equatorial plate)  4. Anaphase: 4n

a. Sister chromatids separate (breaking at centromere), and move to  opposite poles of cell by the spindle shortening

5. Telophase: 4n

a. New nuclei formed, go to opposite poles 

b. Cytokinesis: division of cytoplasm  

i. In animals

1. Cell elongates

2. “pinching in”→ cleavage furrow We also discuss several other topics like viewers make meaning

3. Reformation: nuclear membrane, nucleolus, and chromatin 

appear, spindle disappears

ii. In plants

1. vesicles (little holes) form at the midline, fuse into a plate  

division, which leads to a clear space separation  

C. Cell Division In Bacteria

i. DNA doubles → cell elongates → cytokinesis → two bacteria cells  D. Regulation of Cell Division

i. Contact inhibition: cells stop dividing when surrounded by other cells 1. Putting normal cells in a petri dish: divide until monolayer forms 2. Putting abnormal cells in a petri dish: don’t stop at monolayer, continue  

dividing because they lack proper contact inhibition cell receptors ii. Tumor Suppressor Gene: identifies abnormal DNA, stops those cells iii. Platelet Derived Growth Factor: clamping down on a wound crushes platelets  which release PDGF and cause fibroblasts to come in and divide, healing wound iv. Cyclin Protein/ Regulatory CDPK molecule:

1. Cyclin (protein associated with cell division) determine Mitosis  2. CDPK: Cyclin Dependent Kinase Enzyme, activated (phosphorylates) when cyclin levels rise (in G1, cyclin rises to prep for mitosis), (in  Don't forget about the age old question of final exam schedule gwu

prometaphase, nuclear envelope breaks by kinase phosphorylating  proteins on nuclear membrane)

3. kinase: phosphorylates



A. Meiosis: sexual reproduction of gametes

i. MEIOSIS I: separates homologous chromosomes (mom & dad)

1. Interphase → prepares diploid 2n cell for meiosis by condensing DNA  2. Prophase I: duplicated homologous chromosomes pair up and cross over a. Centrosomes replicate, go to opposite poles, form spindle fibers 

b. Nuclear membrane disappears

c. Crossing over/ gene recombination: tetrads (2 homologous  

chromosomes) pair up (synapsis) and exchange gene segments for  

genetic diversity

3. Metaphase I: chromosomes line up in middle by homologous pairs  a. Independent assortment: the arrangement of lining up can be found  as 2pairs and also leads to genetic diversity

4. Anaphase I: homologous chromosome pairs split apart

a. sister chromatids remain attached

5. Telophase I: arrangement for division

a. Nuclear membrane→ 2 nuclei formed at each pole

b. Cleavage furrow forms

6. Cytokinesis I → 2 haploid n cells

a. Each chromosome de-condenses into chromatin, cells split into two ii. MEIOSIS II: separates sister chromatids

a. DNA is not replicated at this stage

2. Prophase II: chromatin→ chromosomes, nuclear membrane disappears,  centrosomes double up, go to poles, and make spindle fibers  

3. Metaphase II: chromosomes line up in the middle

4. Anaphase II: chromosomes separate → briefly 2n

5. Telophase II: chromosomes → chromatin, nuclear membrane reforms 6. Cytokinesis II → 4 haploid n cells (all different)

iii. Meiosis in males: located in testes

1. one 2n primary spermatocyte, meiosis I→  two n secondary  

spermatocytes, meiosis II and differentiation → four n sperm cells

iv. Meiosis in women: located in ovary

1. One 2n primary oocyte, meiosis I → one secondary oocyte, one polar body,  meiosis II→ one n ovum, 3 polar bodies (dissolve, prevent “litters)

v. Fertilization: one sperm and ovum → zygote which divides by mitosis  1. Identical twins, it zygote splits into two and continues to divide

2. Paternal twins: 2 different eggs and 2 sperm



A. Gregor Mendel: monk and gardener, 1860’s, worked with pea plants and used math  to predict offspring and traits  

i. Fundamental Laws of Inheritance

1. Law of Dominance: a dominant gene (A) will appear

2. Law of Segregation: during meiosis, alleles for a trait separate, each  gamete gets one allele (A or a)

3. Law of Independent Assortment: genes for one trait are independent of  genes for another trait (AA doesn’t care about BB)

B. Traits: exist as 2 alleles on genes,

i. Alleles can be dominant (A) or recessive (a), which only appears if it’s aa 1. On chromosomes, allele is found in the locus (top band)

ii. Phenotype: word description of trait (tall, short)

iii. Genotype: allelic description of trait (AA, Aa, aa)

C. Crossing Traits- Punnett Square









i. AA x aa →Homozygous cross, same allele: all heterozygous

AA is pure breeding

ii. Dihybrid Double Homozygous Cross (AABB x aabb) of two genes 1. F1 (first generation) →  100% dominant heterozygous

2. F2 (second generation)

a. 9/16 A_B_, both dominant

b. 3/16 A_bb and aaB_, one dominant one recessive

c. 1/16 aabb, both recessive

iii. Doubly Heterozygous cross (Aa x Bb) → ¼ AB, ½ aB or Ab, ¼ ab 1. To find chance of AABBCCDD, chance of each homozygous AA (1/4) x # of  traits) so ¼ x 4 = 1/256

D. Inheritance

i. Incomplete dominance: blending of alleles, neither is completely expressed  a. red x white → ½ pink flowers ¼ red, and ¼ white

ii. Codominance: both alleles for a gene are equally expressed

a. each hair is completely red or completely white in the Roan horse iii. Epistasis: stunting of dominant one non-allelic (outside) gene interferes with  expression of a 2nd gene

1. aaBB x AAbb (B is the enzyme to make the A pigment)

a. F1 → doubly heterozygous, all are pigmented

b. F2 → 9/16 pigmented, 7/16 are white (A_bb, aaB_, aabb)


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