BIO Set #3 Ch. 5-6 & 11 Flashcards
DNA, PROTEIN SYNTHESIS, MITOSIS, MEIOSIS, REPRODUCTION, IMMUNE, and GENETICS
Identify the enzyme that replicates DNA (which direction does it work?)
DNA
The enzyme that replicates DNA is called DNA polymerase and it works in the 5’ to 3’ direction
What enzyme separates the DNA for replication and what bonds are broken
DNA
DNA helicase
Breaks the hydrogen bonds between the base pairs on the DNA strands, allowing them to separate and be copied
What stage of the cell cycle does DNA replication take place? Be specific:
DNA
DNA replication occurs during the Synthesis phase (S phase) of the cell cycle
What bonds are broken between complimentary stands of DNA?
DNA
Hydrogen Bonds
between the complementary base pairs:
(adenine with thymine, and cytosine with guanine).
ALWAYS. A -T and C - G
What enzyme bonds DNA fragments in the 3’ to 5’ direction?
DNA
DNA ligase
According to Watson and Crick, DNA replication is…
DNA
semi-conservative,
meaning that each new DNA molecule contains one strand from the original DNA molecule and one newly synthesized strand, with each original strand serving as a template for the new complementary strand (making copies)
Which enzyme reduces the stress during DNA replication?
DNA
topoisomerase
Explanation: Topoisomerase works by temporarily breaking and rejoining DNA strands, allowing the DNA to unwind and relieve the tension created during the unwinding process at the replication fork.
What enzymes are needed for DNA repair and/or mutation repair?
DNA
DNA polymerase (for resynthesis of the damaged region)
DNA ligase (to seal the repaired DNA strand)
DNA glycosylase
Enzyme repair
What is the difference between the leading strand vs. lagging strand?
DNA
Leading strand replicates continuously in the direction of the replication fork
Lagging strand replicates discontinuously in small fragments moving away from the replication fork
Lagging strand replicates discontinuously in small fragments called what?
DNA
Okazaki fragments
What is proofreading in reference to DNA replication? Which enzyme is involved?
DNA
DNA polymerase
DNA polymerases are the enzymes that build DNA in cells. During DNA replication (copying), most DNA polymerases can “check their work” with each base that they add. This process is called proofreading.
Which nitrogenous bases are Pyrimidines and which are Purines?
DNA
Pyrimidine bases are Cytosine, Thymine, and Uracil. (CUT)
Purine bases are Adenine and Guanine (AG)
What is and why is Primase needed?
DNA
Without primase, DNA replication cannot start.
DNA polymerase cannot start building a new DNA strand without a primer, making primase essential for the process of DNA replication.
Creates short RNA primers by binding to a single-stranded DNA template
What is a RNA primer and why is it needed?
DNA
They act as a template for DNA polymerase to begin building a new DNA strand. An RNA primer is a short segment of RNA that acts as a starting point for DNA synthesis during DNA replication.
Key points about RNA primers:
Function: They act as a template for DNA polymerase to begin building a new DNA strand.
Synthesis: An enzyme called primase creates the RNA primer.
Removal: Once the DNA strand is synthesized, the RNA primer is removed and replaced with DNA nucleotides.
If Cytosine is 15% - what are the other nitrogenous base concentrations?
DNA
If Cytosine is 15%, then Guanine will also be 15%, and both Adenine and Thymine will be 35% each.
Explanation:
Chargaff’s rule:
This principle states that in a DNA molecule, the amount of Cytosine always equals the amount of Guanine, and the amount of Adenine always equals the amount of Thymine.
Calculation:
Cytosine (C) = 15%
Guanine (G) = 15%
Therefore, Adenine (A) + Thymine (T) = 100% - (C + G) = 70%
Since A = T, then A = T = 35%
What is a mutation?
DNA
Is the source of variation of all things
What site on the ribosome does the 1st tRNA attach in protein synthesis?
Protein Synthesis
The first tRNA in protein synthesis attaches to the P SITE on the ribosomes,
this is specifically called the “peptidyl” site and is where the initiator tRNA binds to the start codon of the mRNA.
What are 3 similarities between RNA and DNA
Protein Synthesis
nucleotides, which consist of a sugar
phosphate group,
same nitrogenous bases (Adenine, Guanine, and Cytosine)
What are 3 differences between RNA and DNA?
Protein Synthesis
different sugars (ribose sugar)
Base is uracil instead of thymine
RNA is single stranded
DNA is double-stranded,
DNA contains deoxyribose, a
thymine which is found in DNA
What is the anticodon for the codon AUG?
Protein Synthesis
UAC
What kind of bond forms between the amino acids as the protein chain is forming?
Protein Synthesis
peptide bond
it’s a covalent bond formed between the amino group of one amino acid and the carboxyl group of the next amino acid, essentially linking them together to create a polypeptide chain
What enzyme makes RNA and which direction does it work?
Protein Synthesis
5’ to 3’ RNA polymerase bond
What is RNA processing and where does it happen?
Protein Synthesis
RNA processing is the modification of a newly formed RNA transcript, called pre-mRNA, to produce a functional messenger RNA (mRNA) molecule, and it primarily occurs in the nucleus of eukaryotic cells;
this involves removing non-coding regions (introns) and splicing together the coding regions (exons) of the transcript to create a mature mRNA ready for translation into protein.
Key points about RNA processing:
Location: Primarily happens in the nucleus of eukaryotic cells.
Process: Includes adding a 5’ cap to the leading end of the RNA, removing introns, splicing exons together, and adding a poly-A tail to the 3’ end.
Importance: RNA processing ensures that only the correct coding sequence is translated into protein.
What is transcription and where does it happen?
Protein Synthesis
Process of transcribing the DNA by RNA polymerase to make RNA. Takes place in the nucleus.
What is translation and where does it take place?
Protein Synthesis
Wherever there are Ribosomes
Translation takes place on ribosomes in the cell cytoplasm, where mRNA is read and translated into the string of amino acid chains that make up the synthesized protein.
How many codons are needed to build a protein that has 5 amino acids?
Protein Synthesis
5
The codon is located on the:
Protein Synthesis
mRNA
The anticodon is located on the:
Protein Synthesis
tRNA
Indicate the start codon:
Protein Synthesis
AUG
The first tRNA anticodon will always bond with its codon in which site on the ribosome?
Protein Synthesis
P site
How many anticodons are needed to build a protein that has 5 amino acids?
Protein Synthesis
5
A cell with 26 chromatids at the start of MITOSIS will produce cells with ___ chromosomes?
Mitosis
13
What are the anticodons for the stop codons?
Protein Synthesis
UAA, UAG, and UGA,
The stop codons are UAA, UAG, and UGA, and they do not code for any amino acids
What does Diploid and Haploid mean?
Mitosis
Haploid: One set of chromosomes (half chromosome)
Diploid: Two sets of chromosomes (full set chromosome
A cell with 12 chromosomes at the start of MITOSIS will produce cells with ___ chromosomes?
Mitosis
12
What is cytokinesis, explain what happens in animal vs. plant, and what stage does it start?
Mitosis
cytoplasmic division
ANIMAL cells, this happens through a cleavage furrow,
PLANT cells, a cell plate forms down the middle of the cell due to their rigid cell wall, and cytokinesis typically begins during the anaphase stage of mitosis
Cytokinesis is the final stage of cell division where the cytoplasm of a cell divides into two separate daughter cells, essentially “pinching” the cell in two.
What makes a sister chromatid a sister chromatid?
Mitosis
attached to another sister chromatid held by centromere
(identical copy of a chromosome created during DNA replication, joined to its original)
Interphase has 3 sub-phases
- identify those phases, what occurs in each, and time of each phase.
Mitosis
G1 - protein synthesis + metabolism
S (synthesis) - DNA Replication
G2 - preparing for M Phase
cellular growth and preparation for M phase. Two replicated chromosomes (sister chromatids) held together by a centromere.
When is a chromatid a chromatid?
Mitosis
when it is one of the two identical copies of a chromosome that has been replicated in preparation for cell division, meaning it is one half of a duplicated chromosome
What is karyokinesis and what stage does it happen?
Mitosis
karyokinesis is a nuclear division and it happens during the M phase (mitotic phase) of the cell cycle; Anaphase
What is a replicated chromosome?
Mitosis
two sister chromatids
Indicate the role for each of the following structures in mitosis: spindle fibers, centrioles and aster fibers
Mitosis
In mitosis -
SPINDLE FIBERS are responsible for pulling apart the chromosomes during cell division by attaching to the centromeres
CENTRIOLES act as the organizing centers for the spindle fibers
ASTER FIBERS help position the spindle apparatus within the cell by radiating from the centrioles, ensuring proper chromosome alignment and separation to opposite poles of the cell.
Know each mitotic phase and what happens in each phase.
Mitosis
PROPHASE- chromosomes condense and become visible
METAPHASE - they line up at the cell’s equator
ANAPHASE - sister chromatids separate and move to opposite pole
TELOPHASE - new nuclear membranes form around the separated chromosomes, essentially reversing prophase events.
A cell with 12 chromosomes at the start of MEIOSIS will produce cells with ___ chromosomes?
Meiosis
6
A cell with 28 chromatids at the start of MEIOSIS will produce cells with ___ chromosomes?
Meiosis
7
Why do these 3 types of variation happen - mutations, sexual reproduction and crossing over why do these happen ?
Meiosis
Genetic diversity, need for natural selection
Breakdown of the reasons for each type of variation
Genetic Variation:
Mutations: Random changes in DNA sequence that can introduce new traits into a population.
Sexual reproduction: The mixing of genes from two parents during meiosis creates new gene combinations in offspring.
Crossing over: During meiosis, homologous chromosomes exchange genetic material, further increasing variation.
What are the 3 types of variation that occur during gamete formation (give phases) and reproduction?
Meiosis
Crossing over (Prophase 1)
Random fertilization
Independent Assortment (Metaphase 1)
What is a homologous chromosome?
Meiosis
Similar shape, size, gene basically the same but with different alleles
What is a tetrad?
Meiosis
a homologous pair together
What separates in Anaphase 1 in meiosis?
Meiosis
tetrad
What separates in Anaphase 2 in meiosis?
Meiosis
sister chromatids
What is non-disjunction, when does it occur (phases), and give two possible results of it?
Meiosis
failure of pulling tetrad in Anaphase 1
failure of pulling sister chromatids in Anaphase 1
Nondisjunction is a genetic error where chromosomes fail to separate properly during cell division (mitosis or meiosis), resulting in daughter cells with an abnormal number of chromosomes. extra chromosome (trisomy) or a missing chromosome (monosomy).
(Nondisjunction happens during the anaphase stage of cell division when chromosomes are supposed to separate and move to opposite poles of the cell.)
Define trisomy, monosomy, n + 1 and n
Meiosis
TRISOMY (2n+1) the gain of one chromosome (extra copy) resulting in three copies instead of the usual two. (Down Syndrome)
MONOSOMY (n-2) missing one copy of a chromosome, having only one copy instead of the usual two, represented as “2n - 1” (Turner Syndrome). meaning it’s caused by a loss of one X chromosome in females
n + 1:
Represents a gamete (sex cell) that has one extra chromosome compared to the normal number of chromosomes (“n”).
n:
Represents the normal number of chromosomes in a cell
Key points:
Both trisomy and monosomy are considered types of aneuploidy, which means an abnormal number of chromosomes.
“N + 1” signifies a gamete that would result in a trisomy if it fertilized a normal gamete.
These conditions often arise due to a process called nondisjunction during meiosis, where chromosomes fail to separate properly.
Why is meiosis I also called the reduction phase?
Meiosis
Diploid to Haploid
Meiosis I is called the “reduction phase” because during this stage of cell division, the number of chromosomes in the daughter cells is reduced by half, going from diploid (two sets of chromosomes) to haploid (one set of chromosomes), effectively halving the genetic material in each new cell
Why is prophase I and metaphase I important phases?
Meiosis
Variation occurs needed for natural selection.
they are the stages where genetic recombination (crossing over) occurs during prophase I, and where homologous chromosomes randomly align at the equator of the cell in metaphase I, leading to significant genetic diversity in the resulting gametes, a key aspect of sexual reproduction; this random alignment ensures that each offspring receives a unique combination of alleles from their parents.
What happens with synapsis, crossing-over and independent assortment?
Meiosis
synapsis the homologous pairs of sister chromatids line up together and connect, the result of synapsis is a tetrad
Crossing over is the exchange of genetic information between homologous paired chromosomes.
Independent assortment is the separation of those chromosomes into new daughter cells.
What is a zygote?
Meiosis
fertilized egg, NOT an embryo
A zygote is a fertilized egg cell that is formed when a sperm and an egg cell join together. The zygote contains all the genetic information (DNA) required to develop into a baby.
Why is meiosis II similar to mitosis?
Meiosis
Sister chromatid being separated during anaphase
Compare/contrast autosomes and sex chromosomes
Meiosis
Number in humans:
Humans have 22 pairs of Autosomes and one pair of sex chromosomes.
Sex chromosomes are the X and Y chromosomes, with females having two X chromosomes and males having one X and one Y chromosome.
What is a karyotype and why is it important?
Meiosis
picture display of chromosomes.
an individual’s complete set of chromosomes. A karyotype may be used to look for abnormalities in chromosome number or structure.
What is a chiasmata?
Meiosis
two non-sister chromatids from homologous chromosomes attach to each other
Define diploid and haploid
Meiosis
Haploid: One set of chromosomes (half chromosome)
Diploid: Two sets of chromosomes (full set chromosome)
Specific location where sperm is produced?
Reproduction
seminiferous tubules
(located inside the testes)
Where is sperm stored?
Reproduction
epididymis
klWhen the egg is released from the ovary (during ovulation), fertilization will happen where and what stage of meiosis is the egg in?
Reproduction
fertilization typically occurs in the FALLOPIAN TUBE, and the egg is in the METAPHASE II stage of meiosis
What is semen composed of?
Reproduction
sperm, seminal fluid
What are the following and indicated diploid or haploid: primary spermatocyte and secondary spermatocyte?
Reproduction
A primary spermatocyte is a diploid cell , meaning it has a full set of chromosomes (2n)
secondary spermatocyte is a haploid cell it divides into two secondary spermatocytes, which are now haploid (n) as they contain half the number of chromosomes
Know male structures/functions/produce: seminiferous tubule, epididymis, vas deferens, seminal vesicle, prostate gland, & Cowper’s gland
Reproduction
Explanation:
Seminiferous tubule: The primary reproductive organs, responsible for producing sperm and testosterone. (produce sperm cells)
Epididymis: A coiled tube located on the surface of each testis where sperm mature and are stored temporarily.
Vas deferens: A tube that carries sperm from the epididymis to the ejaculatory duct.
Seminal vesicles: Glands that produce a fluid rich in fructose, which provides energy for sperm motility.
Prostate gland: A gland that contributes fluid to semen.
Bulbourethral glands (Cowper’s glands): Glands that secrete a fluid that lubricates the urethra before ejaculation.
Urethra: The tube that carries both urine and semen out of the body.
Know the following female structures/functions/produce: vagina, cervix, uterus, fallopian tube and ovary.
Reproduction
The ovaries produce eggs and hormones, while the fallopian tubes transport the eggs to the uterus.
The cervix acts as a gateway between the vagina and the uterus.
The vagina is the muscular tube that connects the external genitalia to the cervix.
What is spermatogenesis?
Reproduction
production of sperm
What is oogenesis?
Reproduction
production of egg
The alarm substance (triggers an inflammatory reaction) your body releases when cells are damaged and/or invaded by is called?
Immune
Histamine
Identify the physical barriers to invasion by other organisms
Immune
Skin
sweat
waxes
oils
mucus
tears
What is your body’s inflammatory response?
Immune
histamine
When cells get damaged, it releases histamine and causes phagocyte dilation of capillaries and makes them leakier so white blood cells can migrate to those areas and eat the bad stuff, once histamine goes away the capillaries phagocyte constrict and white blood cells sacrificed their life to the greater good
What is a phenotype?
Genetics
the observable characteristics or traits of an organism, such as its appearance, behavior, and development,
Phenotype refers to what you can see or measure about an organism, like eye color, height, or blood type.
What is a genotype?
Genetics
Genetic code for a trait
a “genotype” refers to the genetic makeup of an organism, essentially the complete set of genes an individual inherits from their parents, which determines their potential traits and characteristics
What is a gene and how does an allele relate to a gene?
Genetics
A gene is a specific section of DNA that codes for a particular trait.
An allele is a variant form of that gene (alternative versions of a gene)
Define: homozygous dominant, heterozygous and homozygous recessive
Genetics
In genetics,
“homozygous dominant” means an organism has two copies of the same dominant allele for a gene, both alleles are dominant (AA)
“heterozygous” means it has one dominant and one recessive allele (Aa)
“homozygous recessive” means it has two copies of the same recessive allele for a gene, both alleles are recessive (aa) recessive phenotype
Note: “homozygous” means having two identical alleles, while “heterozygous” means having two different alleles for a trait.
What is the genotypic ratio and phenotypic ratio for monohybrid cross?
Genetics
genotypic ratio is 1:2:1
phenotypic ratio is 3:1
meaning for every
1 homozygous dominant (AA) genotype,
2 heterozygous (Aa) genotypes,
1 homozygous recessive (aa) genotype,
there will be 3 individuals expressing the dominant phenotype and 1 expressing the recessive phenotype.
What is the phenotypic ratio for dihybrid cross?
Genetics
9:3:3:1
A cross between two individuals heterozygous for two different genes
When sex-liked alleles are involved, what does it mean to be a carrier?
Genetics
When discussing sex-linked alleles, a “carrier” refers to an individual,
usually a female, who possesses one copy of a mutated gene on their X chromosome, but does not exhibit the associated disease symptoms because they have a normal copy on their other X chromosome; they can still pass this mutated gene on to their offspring, potentially causing the disease in their male children who only have one X chromosome.
Know how to complete the following genetic crosses: monohybrid, dihybrid, incomplete dominance, codominance and sex-linked.
Genetics
Do the Genetic Problems on your iPad
For sex-linked alleles, why is male treated differently than the female?
Genetics
males only have one X chromosome, while females have two XX
Indicate the different kinds of gametes that could be produced by the following individual AaBBCcDdEE.
Genetics
2n n=heterozygous
There are 3 here, so 2³ = 8
2 x 2 x 2 = 8
AaBBCcDdEE = Aa Cc Dd. (there’s 3)
What does a Punnett square show?
Genetics
the possible genotypes of offspring resulting from a genetic cross between two parents,
Genetic disorders are caused by
Genetics
Mutations and Non-junctions
changes or abnormalities in a person’s DNA sequence, often referred to as “mutations,”
