Ap Bio Exam Flashcards
Linear Electron Flow (Photosystem II)
Photon of light strikes a pigment molecule. Light travels from pigment molecule to pigment molecule until it reaches P680. Electron is then transferred to primary electron acceptor and water is split (H+ is released into thylakoid space). Additionally, two oxygen atoms join together to form O2
Linear Electron Flow (Photosystem II to I)
Photoexcited electrons pass from the primary electron acceptor of Photosystem I to Photosystem II via an ETC. As electrons flow down, protons are pumped into the thylakoid space.
Linear Electron Flow (Photosystem I)
Electrons move from 0700 pair to Photosystem I’s primary electron acceptor. The electrons then go down a second electron transport chain, reducing NADP+ to NADPH
Cyclic Electron Flow
Takes place in PS I & generats ATP
Calvin Cycle (Carbon Fixation)
Carbon from Co2 molecule attaches to a five carbon sugar (RuBP), this six carbon intermediate is so unstable it needs to split into 2 3-carbon molecules
Calvin Cycle (Reduction)
Each 3 carbon molecule recieves a phosphate group from ATP and is reduced and loses a phosphate group to become G3P. For 3 molecules of CO2, six molecules of G3P are produced.
Calvin Cycle (Regeneration)
Only one G3P can be counted as net gain because the other five G3P molecules are used to regenerate 3 molecules of RuBP
Paracrine Signaling
A signaling cell acts on nearby target cells by secreting molecules of a local regulator
Endocrine Signaling
Specialized cells release hormones, where they reach target cells that can recognize and respond to them
RTKs
Binding molecules signal two receptor monomers to join and form a dimer. Each tyrosine kinase adds a phosphate group (from ATP) to the a tyrosine molecule part of the tail. Proteins can now bind to a specific phosphorylated tyrosine
GPCR
cell-surface transmembrane receptor that works with the help of a G protein, typically activating a single transduction pathway. G proteins are in an active state when they bind to GTP.
Where can signals for apoptosis come from?
From the ER when excessive protein misfolding occurs, from the nucleus when DNA has suffered irreparable damage, or when a cell sends a signal to another cell (extracellular)
Prophase
Parent cell duplicated chromosomes condense and mitotic spindle begins to form
Prometaphase
Nuclear envelope breaks down, microtubules grow outward from the centrosomes (which are moving apart) and connect to each chromosome at its kinetochore
Metaphase
Chromosomes align along with the cell equator. Each chromosome has at least two microtubules extending from its kinetochore.
Anaphase
Each chromosome’s sister chromatids separate and move to opposite poles of the cell
Telophase
Chromosomes arrive at the cell poles, mitotic spindle disassembles, and two nuclear envelopes form
Cytokinesis
Cleavage furrow is formed, allowing the cytoplasm to split into two genetically identical daughter cells
Cytokinesis in plant cells
Vesicles from the golgi move along microtubules to the middle of the cell, forming a cell plate. The cell plate expands as vesicles containing cell wall materials fuse, expanding outwards until two distinct daughter cells are formed.
Prokaryotes (division)
Go through binary fission - double their size and divide in half. Origins of replication move towards opposite ends of the cell
How do CDK and Cyclin monitor the cell cycle?
CDK is present at equal levels throughout the cell cycle. However, cyclin levels fluctuate. When cyclin combines with CDK, MPF is produced and when enough MPF accumulates, the cell passes the G2 checkpoint and begins mitosis.
Density-dependant inhibition
crowded cells stop dividing (binding of a cell-surface protein to its counterpart on an adjoining cell sends a signal to both that inhibits cell division.
Prophase 1 (meiosis)
Spindle forms, duplicated chromosomes start to move to opposite sides of the cell, crossing over occurs. Microtubules from one pole or the other attach to the kinetochores, one at the centromere of each homolog
Metaphase 1
Pair of homologous chromosomes arranged at the metaphase plate, each pair lining up independently of other pairs
Anaphase 1
Homologs move towards opposite poles guided by the spindle. The two chromatids of same chromosome move towards the same pole
Three events in meiosis that contribute to genetic diversity
Crossing over, random fertilization, and independent assortment
Crossing Over
DNA molecules of nonsister chromatids are broken and rejoined to each other
Law of segregation
The two alleles for each gene separate during gamete formation
Law of independent assortment
Alleles of genes on nonhomologous chromosomes assort independently during gamete formation
Inversion and Translocation
Inversion - chromosomal fragment reattaches to original chromosome but in reverse orientation. Translocation - chromosomal fragment joins a nonhomologous chromosome.
Genomic imprinting
Variation in phenotype depends on whether an allele is inherited from the male or female parent
Pleiotropic
A gene that influences two or more phenotypes
Epistasis
When one gene locus masks or modifies the phenotype of a second gene locus
5’ end vs 3’ end
5’ end has a phosphate group attached to it & the 3’ end has a hydroxyl group attached to it
Replication Fork
At the end of a replication bubble where the parental strands of DNA are being unwound
Helicases
Untwist the double helix at the replication forks
Single-strand binding proteins
bind to the unpaired DNA strands, keeping them apart