Final Exam Flashcards
What is the products of the Krebs Cycle? Rank them lowest energy to highest.
ATP, CO2 and Electrons and Protons in NADH and FADH2.
ATP –> FADH2 –> NADH
Why does NADH have a lot of energy?
It creates 3 ATP molecules.
How do the carbons go in Krebs/Citric acid cycle?
2 Carbon –> 6 Carbon –> 5 carbon –> 4 carbon –> 2 carbon.
How does the total cycle go to make ATP?
Glycolysis breaks down glucose (creates 2 pyruvate, 3 carbon) –> Pyruvate turns into 2 carbon molecules Acetyl CoA goes through membrane —> Krebs cycle –> Oxidative Phosphorylation. Moves e’ to create gradient.
What are NADH and FADH2?
They are coenzymes that ferry electrons into ETC.
What does beta oxidation do, where does it happen?
Breaks down fatty acids, happens in mitochrondria.
Where does Krebs cycle happen?
Lumen of mitochondria.
Why are carbon and nitrogen not available in gaseous forms?
They are chemically inert and don’t react with anything so they need to be fixed to another molecule, this is why carbon and nitrogen fixation are important.
What do plants do in photosynthesis?
They turn CO2 and H2O into sugar.
What does N2 get turned into?
NH3 (ammonia)
Can eukaryotes fix carbon and nitrogen?
No. They are heterotrophs.
What are autotrophs?
Plants.
Why can plants fix sugars even though they are eukaryotes?
They have prokaryotes inside them, came from cyanobacteria.
Why does NH3 get excreted?
When amino acids are broken down the methyl side group gets excreted as NH3.
What is carbon fixation?
When CO2 get fixed into another molecule.
What does oxygenic photosynthesis produce?
O2
What bacteria gave plants the ability to photosynthesize?
Cyanobacteria
What is a pigment?
A pigment is any colored molecule.
What pigments are in photosynthesis?
Chloryphyll A, B and carotenoids.
What helps in photosynthesis to get light waves?
Carotenoids, xanthopylls capture all lights, except green.
Why are plants green?
Because green does not get absorbed, whatever is not absorbed is the color you see.
What is a chloroplast made of?
-double layer clear outer membrane.
-Stacks of thylakoids, like coins, called granum.
-Stroma is fluid.
-photosynthetic part is inside chloroplast.
What is the antenna complex where is it located?
Located in PS2 and PS1, captures enough energy to knock electrons from pigments into ETC.
Which comes first in the Photosystems?
PS2 then PS1 knocks electrons off water.
What is linear electron flow?
Linear electron flow pumps out NADPH and ATP.
What does cyclical electron flow do?
Cyclical electron flow only makes ATP, electron goes from PS1 out of PS1 and back to it.
What is the purpose of the Calvin Cycle?
CO2 + NADPH + ATP = G3P sugar
What happens in Calvin Cycle?
1) Carbon Fixation - Add one CO2 to a 5 carbon molecule, as carboxyl.
2) Reduction - Add electrons and protons to 3 carbon molecule.
3) Regeneration - Recreate original 5 carbon molecule.
What is G3P?
3 carbon sugar molecule called Glyceraldehyde 3-phosphate.
Where are the light reactions?
In Thylakoids, splits H2O.
Where does the Calvin cycle take place?
In the Stroma.
What is Rubisco?
Rubisco (= ribulose bisphosphate carboxylase)
Takes carbon out of CO2 and fixes to organic compound.
What are 3 types of cell communication?
1) neural signaling
2) Paracrine signaling
3) Endocrine signaling
What is neural signaling?
Nerve cells have contact with each other and relay from nerve cell to nerve cell.
What is paracrine signaling?
Some signal molecules diffuse over a short distance in tissue for nearby cells.
What is endocrine signaling?
Signal molecules go into bloodstream and circulate to target cells throughout the body.
What are cell junctions?
Gap between touching cells, membrane proteins line up to make channels.
What is cell to cell recognition?
Lock and key fit, protein receptors outside cell receive signal molecules.
What does cell signaling do?
It can activate or deactivate genes in nucleus, or another cellular process.
What are hormones?
Signal molecules that go through bloodstream, can be thyroid or steroid hormones.
What are steroid hormones made from? Where are they made?
Cholesterol, they can go through cell membrane easily, made in gonads and adrenal glands. Affect physiological things.
What are thyroid hormones? What do they do? What are they made of?
They control metabolic functions such as energy output, made of Thyroxine (T4) and triiodothyronine (T3), made of amino acid tyrosine with iodine attached.
Do steroids and hormones pass through cell membranes?
Yes and bind to a receptor protein in cytoplasm which then can go into nucleus and activate/deactivate gene.
Can most signal molecules go through membrane?
No.
What is a transduction pathway?
Signaling molecule binds to protein in membrane starting a cascade of protein kinases.
What are protein kinases?
An enzyme that phosphorylates a target protein with ATP, cascades and each keep changing another until signal is reached.
What is a GPCR? How many are there?
G protein couple receptor, ~800 in humans.
What is the structure of GPCR?
7 Alpha helixes, with a hydrophobic middle part, they are transmembrane protein. N terminal outside cell, C terminal inside cell.
How do GPCRs work?
They are bound to GDP (guanosine diphosphate). When signal molecule binds to outside cell, it activates G-Protein inside cell. Binds to GTP then g protein leaves GCPR goes and activates some other molecule. GTP ends as GDP again.
In general, describe the journey taken by proteins, lipids, and carbohydrates as they move and change to become usable energy.
They move from their original form, to then become an amino acid, a fatty acid or a sugar, which then becomes aecytl coA, which then enters to Krebs cycle, which then enters the Electron transport chain in oxidative phosphorylation all to make ATP.
How do cellular respiration and photosynthesis work together?
Complementary. Photosynthesis in plants and algae converts carbon dioxide and water into glucose and oxygen using sunlight, while cellular respiration in animals and plants breaks down glucose and consumes oxygen to produce carbon dioxide, completing a cycle that sustains life on Earth.
Histamine receptors, cannabinoid receptors, and opioid receptors are all examples of this kind of receptor?
GPCR
How many chromosomes would be made with 23 pairs of homologs? How many chromatids?
46 chromosomes total. 92 chromatids.
What are RTKs?
Receptor Tyrosine Kinase
What do RTKs do?
Pair of signaling proteins that come together when they receive signal molecules and then phosphate each other. Most are used for protein growth factors.
What are two basic types of cells?
Prokaryotes and Eukaryotes.
What are chromosomes?
Long strands of DNA containing genes.
How many chromosomes in haploid cell?
23 (gamete), one version of every gene.
How many chromosomes in diploid cell?
46, two complete sets of genes from two parents, 2 versions of each gene.
Which is light and which is dark? Euchromatin and Heterochromatin.
Euchromatin is light, Heterochromatin is dark.
How is DNA condensed?
Onto spools called histones which are then called nucleosomes, they are stacked on top of each other when condensed.
What is interphase made of?
G0 phase sometimes, G1 –> S Phase –> G2 phase.
G1 – > Cell gets all it needs to divide.
S Phase –> DNA replicates, becomes sister chromatids.
G2 –> Cell replenishes to divide, some organelles duplicated, cytoskeleton dismantled. Last phase before mitosis.
What is an X of DNA composed of?
Sister chromatids
What is a karyotype?
An individuals complete set of chromosomes, visible in prophase.
What are steps of mitosis?
Prophase, Metaphase, Anaphase, Telophase, Cytokinesis.
Do chromosomes find homolog pairs in mitosis?
No they just randomly line up on metaphase plate.
What is a chromosome made of in cell division?
A pair of sister chromatids joined by a centromere.
What are alleles?
Alleles are different versions of genes, don’t change location but change allele. Eg may have two different hemoglobin genes.
What is the difference between mitosis and meiosis?
Meiosis is only used for gametes, makes haploid cells.
What is syngamy?
Two gametes coming together.
What do the homologs do in meiosis?
Line up beside each other.
What is synapsis?
the zipping up of homologs to create bivalents (tetrads) and switch parts of genome creating genetic diversity.
How many daughter cells does meiosis make?
4
What is the difference between N and 2n?
N is haploid, 2N is diploid number.
What is the difference between somatic and germline cells? Where are they found?
Germline are in gonads, can do either mitosis or meiosis. Somatic are all other cells in the body, can only do mitosis.
What happens in prophase?
Chromatin condenses into chromosome and become visible.
Nucleolous disappears.
What happens in metaphase? What is different in meiosis vs mitosis?
Chromosomes line up on metaphase plate, attach to microtubules.
What is Meiosis 1 and 2?
Meiosis 1 is where DNA is replicated and DNA shuffling happens when homologous chromosomes line up and homologs separated, Meiosis 2 is where the sister chromatids are pulled apart to form the 4 new cells all genetically diverse.
What are homologs?
Same genes but different versions. One may have red hair one may have brown.
What is diploid?
2 sets of genes from 2 parents, 2 complete sets of genes and chromosomes.
What makes up DNA?
DNA is made of nucleotides.
What are nucleotides made of?
3 parts, Deoxyribose (5 carbon sugar), phosphate group and nitrogenous base.
What are the 4 types of DNA and what are their base pairs?
Adenine (double ring purine), Thymine (single ring pyrimidine), Guanine (Double ring Purine). Cytosine (Single ring pyrimidine).
Base pairs are A-T, G-C.
What is RNA?
polymer of nucleotides made of nitrogenous base, phosphate group and 5 carbon sugar that is ribose with hydroxyl group. Does not have thymine, uses uracil instead. Single stranded.
What does Helicase do?
Breaks hydrogen bonds between DNA unzipping it.
What does DNA polymerase do?
Replicates DNA reading 3’ to 5’
What does Primase do?
Makes a primer to give polymerase a place to start replication.
What does Ligase do?
Ligase glues the DNA fragments together, the Okazaki fragments on lagging strand.
Single Strand DNA binding Protein what does it do?
binds to DNA and makes sure it doesnt stick back together after helicase breaks it apart.
What does DNA code for?
RNA
What does RNA polymerase do?
Binds to a region of DNA and reads it, this is transcription.
What is a transcription unit?
Part of DNA that gets read, within transcription unit is coding region.
What regulates transcription?
A promoter and an enhancer, promoter right next to gene enhancer a bit further away.
What is a promoter?
Promoter tells RNA where to land to start reading code. Initiates gene transcription.
What is enhancer?
Where a protein binds to turn the gene on or off.
What are the 2 types of genes?
Coding and non coding genes, coding is for proteins, non coding is for RNA polymerase.
What is a coding region?
Has the information to synthesize a protein that RNA reads to make a protein.
What are transcription factors?
2000 in humans, they regulate genes, they are proteins involved in turning genes on and off or making them.
What is a myoblast cell?
Undifferentiated skeletal muscle cell, has no RNA. Differentiated cells have RNA.
Does DNA/Genes change when cell is differentiated?
No.
What is MYoD?
a protein and transcription factor that binds early to enhancer in undifferentiated muscle cell that activates expression of myogenin gene.
What is myogenin?
another transcription factor, that can bind to other genes to express them also.
What does DNA methylation do?
stops genes from being expressed. It is when a cystine group gets a methyl side group attached to it.
Do muscle cells and neuron cells differentiate again after birth?
No, fixed amount. this is why muscle has satellite cells.
What do satellite cells do?
Only in adult muscle cells, they differentiate into muscle after damage.
What is the definition of a gene?
A gene is physical and composed of DNA. Has 2 parts.
1) Transcription unit: gives output to make product, read by RNA polymerase. 2) regulatory region: On the same part of DNA, decides when, where and how much to be made.
What cells in body have myogenin gene?
All cells.
Which cells in thebody have myogenin mRNA?
Skeletal muscle cells.
Which cells in body have MyoD protein?
Skeletal muscles.
In what part of gene is the coding region located?
The transcription unit.
What is the function of all transcription factors?
A protein that initiates and regulates gene expression.
Why do we need to have satellite stem cells lining our muscles?
Born with fixed amount, so when we grow or damage muscles we need something to replace it damage.
Give an example of a cell in which myogenin gene would be methylated.
Neuron, Skin cell, Stomach cell.
What happens if MyoD is mis expressed in chondrocytes?
Then that cell would turn into a muscle cell as those genes have now been expressed.
What does MyoD protein bind to?
MyoD binds to enhancer to start expressing the myogenin gene.
Which of these are not composed of DNA?
1) Promoter
2) Transcription Factor
3) RNA polymerase
4)Enhancer
5) Transcription unit
6) mRNA
1) Yes
2) Yes
3) No
4) Yes
5) Yes
6) No
What’s the difference between RNA and DNA?
DNA polymerase produces a double-stranded DNA molecule while RNA polymerase produces a single-stranded RNA molecule.
What happens in Anaphase?
Sister chromatids are separate.
What happens in Telophase?
Nucleus reappears and chromosomes uncondense.
What is cytokinesis?
When cell pinches into two new cells, using actin filaments to separate cytoplasm and organelles.
What are the differences that happen in Meiosis and not Mitosis?
In meiosis 1, in Prophase recombination occurs called synaptonemal complex creating bivalents.
Anaphase 1 does not pull apart sister chromatids, keeps them together.
What is another name for a bivalent?
Tetrad
Are homologs identical?
No, they are similar but not identical, same genes but not same alleles.
Are sister chromatids identical?
Yes.
Is there an second S phase in Meiosis?
No, there is no S phase between the first part of meiosis and the second part.
Explain the what the Krebs cycle achieves?
It is the catabolism of products that happens in the inner membrane of the mitochondria, involving substrates and products while releasing energy.
Is the Krebs cycle exergonic?
Yes, it is completely exergonic, releases energy in small bits.
