Bio chapters 6-10 exam 2
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The process by which plants, autotrophic protists, and some bacteria use light energy to make sugars and other organic food molecules from carbon dioxide and water.
The equation for photosynthesis:
6 CO2 + 6 H2O ------ light & energy ----> C6H12O6 + 6 O2
Photosynthesis occurs in two main stages;
light reactions, and the Calvin cycle.
In light reactions....
Basically the light (input) strikes chlorophyll a in such a way as to excite electrons to a higher energy state. In a series of reactions the energy is converted (along an electron transport process) into ATP and NADPH. Water (input) is split in the process, releasing oxygen (output) as a by-product of the reaction, and gas (output).
Dark reactions use ____ from the light cycle.
In a light reaction, solar energy is converted into....
What is The main electron donor in the light dependent reactions?
essentially the hydrogen that is attached to water.
What are the inputs and the outputs of the Calvin Cycle?
sugar & other organic molecules (outputs) from carbon dioxide (input).
Where does the Calvin cycle occur?
This occurs in the stroma, which are located in the chloroplast!
A light harvesting unit of a chloroplasts thylakoid membrane and consists of of several hundered ANTENNA molcules, a reaction center chlorophyll. and a primary electron acceptor.
How is energy generated in photosynthesis?
because when a pigment molecule absorbs a photon, one of the pigment’s electrons gains energy and the electron raises from a ground state to an excited state. Because the excited state is very unstable, the excited electron usually loses its excess energy and falls back to its ground state.
why is chlorophyll green?
because; chlorophyll and the other pigments built into the membranes of grana mainly absorb light in the blue-violet and red-orange part of the electromagnetic spectrum (this part of the light spectrum is most important for photosynthesis). The pigments do not absorb much green light-which is why we see green-it is reflected!
What did Englemann discover in his experiments?
Englemann observed that oxygen-seeking bacteria migrate toward algae exposed to certain colors of light by using a string of cells suspended in water on a microscope slide. He discovered that blue-violet and orange-red wavelengths best drive photosynthesis.
How do C4 plants perform photosynthesis??
Well, C4 plants actually do close their stomata but are still able to perform photosynthesis thanks to a super helpful enzyme! This enzyme is attracted to CO2 and actually produces a four-carbon compound that shuttles CO2 to the calvin cycle.
What are some C4 plants?
Some miraculous plants that have this capability include; corn and sugarcane!
How do CAM plants perform photosynthesis?
by opening its stomata and allowing CO2 to enter at night! The same enzyme that is found in C4 plants is also found in CAM plants! Here, this enzyme collects the CO2 at night and actually releases it to the Calvin cycle during the day!
what happens during asexual reproduction?
Asexual reproduction does not fertilize from an egg and a sperm, instead it inherits all their chromosomes from a single parent.
How do single-celled organisms reproduce?
Single-celled organisms reproduce by simple cell division=clones.
Sexual Reproduction requires ...
fertilization from a sperm and an egg.
how is DNA is packed into eukaryotic cells?
DNA is packed into eukaryotic cells using an elaborate, multilevel system of coiling and foiling resulting in highly condensed chromosomes. A crucial aspect of DNA packing is the association of the DNA with small proteins called histones (found only in eukaryotic cells).
Are histones found in eukaryotic or prokaryotic cells?
(found only in eukaryotic cells).
What do Chromosomes contain? a single long DNA molecule, typically bearing thousands of genes.
Chromosomes contain a single long DNA molecule, typically bearing thousands of genes.
What are Chromosomes are made up? of material called chromatin (a combination of DNA and protein).
Chromosomes are made up of material called chromatin (a combination of DNA and protein).
How many chromosomes do humans have?
Humans have 46 chromosomes.
Where may one find sister chromatids?
in mitosis! when you see the doubling of the one chromosome. they are held together by a centromere.
What are Homologous Chromosomes ?
Homologous Chromosomes include the 'pairing' up of the maternal chromosome with the paternal chromosome (which is usually observed in meiosis 1).
What happens during Interphase?
Most of the cell cycle is spent in interphase, typically interphase last for 90% of the cell cycle. While in interphase a cell performs normal functions within the organism, doubles everything in the cytoplasm, increases supply of proteins, increases the number of many of its organelles, grows in size, and most importantly chromosomes duplicates.
the cell plate formed ?
by the fusion of many vesicles produced in the golgi apparatus.
what happens to the chromosomes during mitosis?
The chromosomes double and the two sets become two seperate nuclei.
What happens to homologuous pairs in meiosis I?
what happens in meiosis II to the daughter cells???
they yield with a haploid set of chromosomes.
What are the stages of MEIOSIS?
- -Prophase I
- -MEtaphase I
- -Anaphase I
- -Telophase I
- -Meiosis II
- -Anaphase II
What happens in prophase I of meiosis?
Homologuous pairs stick together in pairs which equals four chromatids (they CROSS OVER =)
what happens in METAphase I of meiosis?
Homologuous pairs LINE up!
What happens in meiosis II?
the shsiter chromatids finally seperate which = four haploid daughter cells!!
what are the three main stages of cellular respiration?
- citric acid cycle
- electron transport
What happens during glycolyiss?
The splitting of sugar. Here a six-carbon glucose molecule (input)is broken in half by enzymes, and two molecules of pyruvic acid (output) are eventually formed. 2 ATP are created from direct synthesis. 2 NADH are created. The enzymes that are used here are located in the cytosol.
What happens during the citric acid cycle?
Pyruvic acid, that is left over from glycolysis is “prepped” and becomes acetic acid (input) so that it may be used in this cycle. The acetic acid is broken down all the way to CO2 (output). 2 ATP are created from direct synthesis. 2 NADH are created The enzymes used here in this process are dissolved in the fluid within the mitochondria.
What happens during electron transport?
Here an electron transport chain is used that captures the energy released from the “fall” of electrons. The energy is then used to pump hydrogen ions across the inner mitochondrial membrane. Potential energy is stored in the ions because ions become more concentrated on one side of the membrane than on the other because they are being pumped by the electron transport chains. ATP synthase occurs, and basically proteins use the energy of a hydrogen concentration gradient to make 34 ATP (output). 6 NADH & 2 FADH2 are created.
Where does most of the ATP from the glycolysis and citric acid cycle come from ?
What happens during a redox reaction?
transfer electrons from fuel molecules to NAD+, which forms NADH. 38 ATP total are produced over all throughout the process of cellular respiration -usually, there may be a few more or less molecules.
What happens to energy during a redox reaction?
energy is given off. This energy is used to generate ATP from ADP!
WHat is fermentation?
Anaerobic (without oxygen) harvest of energy
Where may fermentation occur?
Fermentation occurs in both human muscle cells and microorganisms (like fungi and bacteria! Think yeast!) .
explain the process of fermentation in human muscle cells.
when muscle cells consume ATP faster than O2 can be supplied for cellular respiration, they regenerate ATP by fermentation. (notice the importance of ATP!) The waste product under these conditions is lactic acid, that's what our muscles produce when they are sore from being used! Notice that the ATP yield per glucose during fermentation is much lower than the yield of ATP in cellular respiration.
occurs when a haploid sperm cell fuses with a haploid egg cell.
TWO homologous sets of chromosomes. Humans as well as most plants are diploid.
A single chromosome set. IT has only one member from each homologuous pair. The haploid number in humans is 23.
the member of a chromosome pair fail to separate at anaphase. Gametes with abnormal number of chromosomes are the result. This can lead to an abnormal number of sex chromosomes. The most common is an extra X in males a condition called Klinefelter syndrome which causes men to have smaller testis and are sterile.
A severely deranged cell cycle control system. They divide excessively, but they also exhibit other kinds of bizarre behavior.
Cancer treatments include:
Radiation therapy exposes to high-energy radiation which disrupts cell division. Chemotherapy causes cells to stop reproducing.
Varities for which self-fertilization produced offspring all identical to the parent. Mendel worked until he found true-breeding in the plants.
Parent plants differ in only one characteristic.
Mendel's law of Segregation:
A sperm or egg carries only one allele for each inheritied chracteristic because the two members of an allele pair segregate (seperate) from each other during the production of gametes.
Crossing parental variety
Law of independent assortment:
The inheritance of one characteristics has no effect of another.
A mating between an individual of unknown genotype and a homozygous recessive individual. The possible results of Mendel's pea plants could either be All purple or 1 purple:1 white. After reviewing the results of the offspring one could determine the genotypes of the parents. Using a punnet square would help this determination.
What does a family pedigree show?
shows the history of a trait in a family and allows geneticists to analyze human traits
A recessive disorder:
most disorders are recessive. Individuals who carry the recessive allele are carriers of the disorder and seem totally normal.
Chromosome theory of inheritance:
genes are located at specific positions on chromosomes and that the behavior of chromosomes during meiosis and fertilization accounts for inheritance patterns.
Linked genes tend to be...
inherited together as a set.
How can two linked genes give rise to four different gamete genotypes?
During meiosis, crossing over between homologous chromosomes shuffles chromosome segments in the haploid daughter cells which produce a new combination of alleles!
What is a linkage map used for?
A linkage map is used by geneticists to show where genes are located on chromosomes - like a map of genes!
How is sex determined?
A linkage map is used by geneticists to show where genes are located on chromosomes - like a map of genes!
Any gene located on a sex chromosome is a...?
sex linked gene. The X chromosome contains many more genes than the Y; therefore, most sex linked genes unrelated to sex determination are found on the X chromosome.
A chromosome not directly involved in determining the sex of an organism; in mammals, any chromosome other than X or Y.
Te process of two consecutive nuclear divisions in the formation of germ cells in animals and of spores in most plants, by which the number of chromsosomes ordinarily is reduced from the diploid number found in somatic cells to the hapoid.
Wht are nucleotides??
DNA and RNA are both nucleic acids, which consist of long chains (polymers) of chemical units (monomers).
What are polymers?
Large molecules consisting of many identical or similar molecular units which are called monomers. these are joined together in a chain.
What are monomers?
a chemical subunuit that serves as a building block for polymers.
What are nucleotides joined together by?
Nucleotides are joined by a sugar-phosphate backbone.
What are the bases for DNA?
A C G T
What are the bases for RNA?
A C G U
What kind of sugar is DNA made of ?
what is Deoxyribose ?
Deoxyribose is a sugar which makes up the 'backbone' for the structure of DNA.
What sugar is found in RNA?
what is ribose?
the five carbon sugar component of RNA. it is a monosacharide.
What are phosphates?
A functional group consisting of a phosphorous atom covalently bonded to four o2 atoms.
How many strands are found in a DNA strand?
How many strands are there in an RNA?
What are some monomers that build nucleic acids?
Carbohydrates and proteins are monomers that build nucleic acids.
What are nucleotides made up of?
Each nucleotide consists of a nitrogenous base, a sugar and a phosphate group.
What happens when a cell reproduces?
When a cell reproduces, a complete copy of the DNA must pass from one generation to the next. Watson and Crick's model for DNA suggested that DNA replicates by a template mechanism, with each DNA strand serving as a mold, or template, to guide reproduction of the other strand).
What is the product of replication?
Replications results in two daughter DNA molecules, each consisting of one old strand and one new strand. (The parental strand untwists as its strands separate and the daughter DNA rewinds as it forms).
Where does DNA replication begin?
DNA replication begins at specific sites on a double helix, called origins of replication, proceeding in both directions creating replication bubbles.
Enzymes that make the covalent bonds between the nucleotides of a new DNA strand
What is the primary function of DNA?
DNA functions as the inherited directions for a cell or organism, it dictates the production of a polypeptide.
the synthesis of proteins in two stages
What are the two stages of protein synthesis?
Transcription and translation.
What is transcription?
transfer of genetic information from DNA into an RNA molecule
What is translation?
transfer of information from RNA into a protein
linear sequence of nucleotide bases.
A typical gene consists of 1000's of nucleotides.
- A typical gene consists of 1000s of nucleotides
- * A single DNA molecule may contain thousands of genes
What happens to the bases in transcription??
Substitutes Uracil (U) for thymine (T). (Remember! - U pairs with A)
What are the three stages of transcription?
What happens in the initiation of transcription??
- * “start transcribing” signal is a nucleotide sequence called a promoter.
- * RNA polymerase attaches to the promoter
- * RNA nucleotides are linked by RNA polymerase activity.
What happens during elongation in transcription?
- * RNA grows longer
- * RNA strand peels away from the DNA template
What happens during the termintaion of transcription?
- * RNA polymerase reaches a sequence of DNA bases called a terminator
- * Polymerase detaches from the RNA and the 2 DNA strands rejoin
What happens during the processing of eukaryotic RNA?
- * RNA processing includes:
- * Adding a cap and tail
- * Removing introns (stays inside) and splicing exons (exits the nucleus) together to form messenger RNA (mRNA)
What happens during translation?
* Conversion from the nucleic acid language to the protein language.
What is required for translation?
- * mRNA carrying the message (order of the amino acids in the protein to be made) (makes 3 types of ribosomes)
- * energy
- * Enzymes to move the molecules around
- * Ribosomes to catalyze the peptide bond formation
- *Transfer RNA (tRNA) carrying the amino acids
tRNA matches amino acids with codons in mRNA using...
is a molecular interpreter for RIBOSOMES
what are the functions of ribosomes in translation?
- * Coordinate the functions of mRNA and tRNA
- * made of two protein subunits and ribosomal RNA (rRNA)
- * fully assembled ribosome holds tRNA and mRNA for use in translation
What are the three phases of translation?
what happens in initiation during transcription?
- a) mRNA molecule binds to a small ribosomal subunit, then an initiator tRNA binds to the start
- codon (AUG on mRNA)
- b) large ribosomal subunit binds, creating a functional ribosome
What happens during elongation in transcription?
- a) Codon Recognition: anticodon of an incoming tRNA pairs with
- the mRNA codon at the A site of the ribosome.
- b) Peptide bond formation:
- * polypeptide leaves the tRNA in the P site and attaches to the amino acid on the tRNA in the A
- site acids
- * ribosome catalyzes the bond formation between the two amino acids
what happens in translocation?
- * P site tRNA leaves the ribosome
- * tRNA carrying the polypeptide moves from the A to the P site
Any change in the nucleotide sequence of DNA is called
What happens in termination of transcription?
- * Elongation continues until:
- * ribosome reaches a stop codon
- * completed polypeptide is freed
- * ribosome splits into its subunits
what can mutations do?
Mutations can change the amino acids in a protein.
Mutations may involve...
* Large regions of a chromosome or a single nucleotide pair
* Mutations within a gene can occur as a result of:
- * base substitution: replacement of one base by another
- * nucleotide deletion: loss of a nucleotide
- * nucleotide insertion: addition of a nucleotide
Why are mutations neccessary?
- Although mutations are often harmful, they are the source of genetic diversity, which is
- necessary for evolution by natural selection
- * Viruses exhibit some, but not all, characteristics of living organisms.
- * Are not cellular and cannot reproduce on their own.
- * Viruses possess genetic material in the form of nucleic acids (either DNA or RNA)
What are bacteriophages?
Viruses that attack bacteria
What happens during the lyctic cycle?
- Many copies of the phage are made within the
- bacterial cell, and then the bacterium lyses (breaks open)
What happens during the lycogen cycle?
- phage DNA inserts into the bacterial chromosome
- * bacterium reproduces normally, copying the phage at each cell division
viruses that effect plants may...
- * Stunt growth and diminish plant yields
- * Spread throughout the entire plant
- * Viral plant diseases have no cure; best prevented by producing plants that resist viral infection
- * common causes of disease
- * may have RNA or DNA genomes
- * Some animal viruses steal a bit of host cell membrane as a protective envelope.
are subcellular infectious particles that are small circular RNA molecules that do not encode proteins
Are other subcellular infectious particles that are misfolded proteins that somehow convert normal proteins to the misfolded prion version.
Prions are responsible for neurodegenerative diseases including:
- * Mad cow disease and Scrapie in sheep and goats
- * Chronic wasting disease in deer and elk
- * Creutzfeldt‐Jakob disease in humans
What is the difference between a virus, a virioid and a prion?
They are all sub-cellular infectious particles that can cause diseases, but they are structurally different.
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