Bio 7-9 excel export csv Flashcards
3 stages of DNA replication
- enzymes (helicases) bind to the DNA molecule 2. the helicases separate the two strands of DNA, and DNA polymerase helps attach to new, incoming DNA nucleotides one at a time onto the surface of the exposed strands. nucleotides enter their position according to base-pairing 3. result = two identical double-stranded DNA molecules
accessory pigments
pigments other than the green chlorophylls that are commonly found in plants. ex: carotenoids
all organisms use nucleic acids as their genetic material to:
- store information that determines the characteristics of cells and organisms 2. direct the synthesis of proteins essential to the operation of the cell or organism 3. chemically change (mutate) genetic characteristics that are transmitted to future generations 4. replicate prior to reproduction by directing the manufacture of copies of itself
carbon dioxide undergoes carbon fixation, which occurs in where?
the calvin cycle
discrete packags of light energy is called:
photons
electrons released from photosystem ____ end up in the chlorophyll molecules of photosystem ____
2,1
genetic information controls many cellular processes including:
- digestion and metabolism of nutrients / elimination of harmful wastes 2. repair/assembly of cell parts 3. reproduction of offspring 4. the ability to control when and how to react to changes in the environment 5. coordination and regulation of all life’s essential functions
grana
consist of stacks of individual membranous sacs, called thylakoids, that contain chloraphyll
photosystems
arranged clusters of chlorophylls and other pigments involved in trapping sunlight energy and storing it
stroma
the spaces between the membranes
thylakoids
sacs containing chlorophylls, accessory pigments, electron-transport molecules, and enzymes
what are the base pairs for DNA
A (adenine) pairs with T( thymine), G (guanine) pairs with C (cytosine)
what are the three distinct events in the photosynthetic pathway
- light-capturing events 2. light-dependent reactions 3. light-independent reactions
what are the two distinct regions of chloroplasts?
grana and stroma
what happens in the light-capturing events of photosynthesis?
light energy is captured by chlorophyll and other pigments, resulting in excited electrons
what happens in light-dependent reactions of photosynthesis
the energy of the excited electrons is used to disassociate water molecules into hydrogen and oxygen, and the oxygen is released. ATP is produced and NADP+ picks up hydrogen released from water to form NADPH.
what happens in light-independent reactions
ATP and NADPH are used to help combine CO2 w/ a 5-carbon molecule, so that organic molecules, such as glucose, are produced.
what is the equation that summarizes the chemical rxns that photosynthetic organisms use to make ATP and organic molecules
light energy + carbon dioxide + water —> glucose + oxygen
what kinds of prokaryotic organisms are capable of manufacturing organic compounds using light energy
cyanobacteria
which kinds of organisms use respiration to generate ATP?
plants, animals and algae
how do cells use DNA and RNA differently?
DNA is found in the cell’s nucleus and is the original source for information to make proteins. RNA is made in the nucleus and then moves into the cytoplasm of the cell where it becomes directly involved in the process of protein assembly.
how are proteins synthesized?
in two steps: transcription and translation
step one: transcription
Making RNA. the process of using DNA as a template to synthesize RNA. In eukaryotic cells, occurs in nucleus. Messenger RNA carries the blueprint for making the necessary protein. Transfer RNA and ribosomal RNA are used to read the mRNA and bring the necessary amino acids together for assembly into a protein.
step two: translation
Making Protein. the process of using the information in RNA to direct protein synthesis by attaching amino acids to one another. In eukaryotic cells, occurs in cytoplasm. mRNA is read through codons (sets of three nucleotides that cosed for the placement of a specific amino acid). 3 steps of translation: initiation, elongation & termination
epigenetics
changes in gene expression caused by factors other than alterations in a cell’s DNA. do not alter the nucleotide sequence.
mutation
any change in the DNA sequence of an organism
point mutation
a change in a single mucleotide of the DNA sequence
types of point mutations
missense mutation: causes the wrong amino acid to be used in making a protein. silent mutation:a nucleotide change that results in either the placement of the same amino acid or a different amino acid but does not cause a change in the function of the completed protein. nonsense mutation: causes a ribosome to stop protein synthesis by introducing a stop codon too early.
chromosomal aberration
a major change in DNA that can be observed at the level of the chromosome
4 types of aberrations:
inversion: occurs when a chromosome is broken and a piece becomes reattached to its original chromosome, but in flipped orientation. translocation: a broke segment of DNA becomes integrated into a different chromosome. duplications: a portion of a chromosome is replicated and attached to the original section in the sequence. deletion: result when a broken piece becomes lost or destroyed before it can be reattached
genetic information is stored in what type of chemical?
nucleic acids
what is the difference between a ribose and a deoxyribose?
an oxygen atom
transcription copies genetic information from:
DNA to RNA
the function of tRNA is to:
carry an amino acid to a working ribosome
enhancers
increase the transcription of specific genes
splicing
the process that removes introns and joins exons from mRNA
a deletion of a single base in the protein-coding sequence of a gene will likely create
a frameshift
what is the sequence of events of HIV in replication?
RNA—>DNA—>RNA
if the two subunits of a ribosome do not come together with an mRNA molecule, what won’t occur?
translation
what are the three types of cell division?
binary fission, mitosis & meiosis
binary fission
a method of cell division used by prokaryotic cells. requires only one parent that divides and results in two organisms that are genetically identical to the parent. form of asexual reproduction.
mitosis
a method of eukaryotic cell division resulting in daughter cells that are genetically identical to the parent cell.
meiosis
a method of eukaryotic cell division that results in daighter cells that have half the genetic information of the parent cell yet not identical & can be used in sexual reproduction.
the cell cycle:
interphase (3 stages) G1, S, & G2. G1=cell produces tRNA, mRNA, ribosomes, and enzymes for everyday processes. S=cell synthesizes DNA & replication occurs. G2=cell produces the proteins necessary for dividing ie: spindles. After interphase the cell enters mitosis (4 stages) prophase, metaphase, anaphase, and telophase. the nucleus is replicated in mitosis and two cells are formed by cytokinesis. Once certain organs have completed development, some cells can enter the G0 stage where they stop dividing.
key events of prophase (mitosis)
chromosomes condense, spindle and spindle fibers form, nuclear membrane disassembles, nucleolus disappears
difference in spindles in plants and animals
in animal cells, the spindle forms between centrioles. in plants, the spindle forms without centrioles
key event of metaphase (mitosis)
chromosomes align at the equatorial plane of the cell
key event of anaphase (mitosis)
sister chromatids move toward opposite ends of the cell
key events of telophase (mitosis)
spindle fibers dissasemble, nuclear membrane re-forms, chromosomes uncoil, \nucleolus re-forms
cytokinesis
the process during which the cell contents are split between the two new daughter cells. in animal cells cytokinesis results from the formation of a cleavage furrow. in plant cells a cell plate begins to form at the center of the cell and grows out to the plasma membrane.
zygote
the original single cell that results from the union of an egg and sperm. contains two sets of genetic information on 8 chromosomes (4 from the egg and 4 from the sperm-two sets of chromosomes)
determination
the cellular process of deciding which genes a call will express when mature. marks the point where a cell commits to becoming a certain kind of cell and starts down the oath of becoming that cell type.
differentiated
when a cell reaches the end of its determined path, it is said to be differentiated, having become a particular cell type
what is the difference in responsibilities when it comes to mitosis and meiosis
mitosis is responsible for growth and repair of tissues. Meiosis is responsible for the production of eggs and sperm.
haploid vs diploid
H-carry only one complete set of their genetic information D-carry two complete sets of their genetic information
gamete
a general term for egg and sperm
fertilization
the joining of genetic material from two haploid cells. each gamete contributes one set of genetic information toward forming a new organism.
prophase 1 (meiosis 1)
nuclear membrane is broken down and the spindle begins to form. nuclear membrane begins to disintegrate and the chromosomes can be moved throughout the cell.
metaphase 1 (meiosis 1)
homologous chromosome pairs attach to spindle fibers and align the equator
anaphase 1 (meiosis 1)
the two members of homologous pairs of chromosomes separate from each other as they move toward the poles of the cell.
telophase 1 (meiosis 1)
two newly forming daughter cells are now haploid b.c. each contains only one of each pair of homologous chromosomes; nuclear membranes and nucleoli re-form; spindle fibers fragment; chromosomes unwind and change from chromosomes to chromatin.
prophase 2 (meiosis 2)
two daughter cells are preparing for the second division of meiosis
metaphase 2 (meiosis 2)
each chromosome lines up on the equatorial plane and are composed of 2 chromatids joined at a centromere
anaphase 2 (meiosis 2)
centromeres separate, and the chromatids, now called daughter cells, move to opposite poles
telophase 2 (meiosis 2)
4 haploid cells are formed, nuclear membranes & nucleoli re-form, spindle fibers fragment, chromosomes uncoil and change from chromosomes to chromatin. these cells become the sex cells (egg or sperm)
allele
a specific version of a gene. Examples of alleles are:blood type A versus blood type O, dark versus light skin, normal versus sickle-cell hemoglobin, and attached versus free earlobes
difference between crossing over and mutations
crossing over is when 2+ chromosomes interchange on the genetic structure, allowing a new combo of genetic information to occur. mutations are a change in the genetic structure of the whole DNA sequence of an organism, introducing new genetic info to the population.
segregation
the process during which the alleles on homologous chromosomes separate correctly during meiosis 1.
nondisjunction
occurs when homologous chromosomes do not separate during meiosis. ex: downs syndrome, happens if a gamete with 2 number 21 chromosomes has been fertilized by a gamete containing the typical one copy of chromosome number 21 = zygote with 47 chromosomes
what is the difference between mitosis and meiosis
mitosis produces cells genetically identical to the parent, whereas meiosis prodices cells with half the genetic information as the parent
which phase does the replication of DNA occur in?
interphase
chromosomes are most likely to appear to be lining up near the middle of the cell during which phase of mitosis?
metaphase
why can p53 mutations lead to cancer?
b.c. DNA damage is not repaired, mutated cells are allowed to grow, and multiple mutations in the cell’s regulatory proteins occur
at what phases does the genetic information transition from diploid to haploid?
metaphase 1 (last diploid state), anaphase 1 (transition stage), telophase 1 (first haploid stage)
reduction division occurs in …
meiosis 1
trisomy means
three copies of a chromosome are present
which kind of cell division is characterized by a. homologous chromosomes not crossing over and b. centromeres dividing in anaphase
mitosis
