Bio Study Guide - Unit 2 - Sheet1 Flashcards
What does DNA stand for?
deoxyribonucleic acid,
What is the structure of DNA?
Double-stranded helix.
What is the structure of RNA?
Usually single-stranded.
What sugar does DNA contain?
Deoxyribose.
What sugar does RNA contain?
Ribose.
What are the bases in DNA?
Adenine, Guanine, Cytosine, Thymine.
What are the bases in RNA?
Adenine, Guanine, Cytosine, Uracil.
What is the function of DNA?
Stores genetic information.
What is the function of RNA?
Involved in protein synthesis.
How stable is DNA?
More stable.
How stable is RNA?
Less stable.
Where is DNA located?
Primarily in the nucleus.
Where is RNA located?
Throughout the cell.
What are the four macro molecules?
Proteins, Lipids, Carbohydrates, Nucleic Acids
What is the function of Helicase?
Unwinds DNA.
What are Okazaki fragments?
Fragments of copied DNA on the lagging strand.
What is the Leading Strand?
Continuously copied strand (3’ to 5’ template).
What is the function of DNA Ligase?
Binds Okazaki fragments.
What is the function of DNA Polymerase?
Builds new DNA strand by adding complementary bases.
What is the function of Single-Strand Binding Proteins (SSBs)?
Stabilizes DNA during replication.
What is the Lagging Strand?
Discontinuously copied strand (5’ to 3’ template).
What is the function of Primase?
Creates RNA primer for DNA synthesis.
Types and purposes of Cellular replication?
Asexual Replication, Sexual Replication
Asexual Replication
To produce genetically identical offspring from a single parent, resulting in growth, repair, or asexual reproduction. The offspring are clones of the parent cell.
Sexual Replication (Meiosis)
To produce gametes (sperm and egg) with half the chromosome number of the parent cell, ensuring genetic diversity and enabling reproduction through fertilization. The offspring inherit a combination of genetic traits from both parents.
Phases of Interphase
G1 - S - G2, cell spends 90 percent of time in Interphase
What happens during Interphase before entering mitosis?
The cell grows and replicates its DNA (S phase) before entering mitosis.
What happens during Prophase?
The DNA condenses into chromosomes, microtubules appear, and the nucleolus disappears.
What happens during Prometaphase?
The nuclear membrane breaks down, and microtubules attach to the chromosomes.
What happens during Metaphase?
The chromosomes align at the center of the cell.
What happens during Anaphase?
The sister chromatids separate and move to opposite poles of the cell.
What happens during Telophase?
New nuclear membranes form around the chromosomes, and the chromosomes uncoil.
What happens during Cytokinesis?
The cell divides into two daughter cells.
purpose of transcription
The purpose of transcription is to convert a segment of DNA into messenger RNA (mRNA), which carries the genetic information from the DNA to the ribosome for protein synthesis.
purpose of translation
The purpose of translation is to convert the mRNA sequence into a corresponding amino acid sequence, forming a protein. This process occurs at the ribosome in the cytoplasm.
What is RNA polymerase?
RNA polymerase is the enzyme that carries out transcription by synthesizing RNA from a DNA template.
What is the genetic code?
The genetic code is the set of rules by which information encoded within genetic material (DNA or RNA sequences) is translated into proteins by living cells.
What are proteins?
Proteins are complex molecules composed of amino acids, carrying out various functions within the cell.
What are chromosomes?
Chromosomes are structures within cells that contain DNA, organized into genes.
What is gene expression?
Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product (often a protein).
What is a promoter?
A promoter is a region of DNA that initiates transcription of a particular gene.
What is the template strand?
The template strand is the DNA strand used as a template for RNA synthesis during transcription.
What is the coding strand?
The coding strand is the DNA strand that has the same sequence as the mRNA (except for T replaced by U). Also known as the non-template strand.
What is the nontemplate strand?
The nontemplate strand is the DNA strand not used as a template for RNA synthesis during transcription; also known as the coding strand.
What is a codon?
A codon is a three-nucleotide sequence in mRNA that specifies a particular amino acid.
What is translation?
Translation is the process of synthesizing a protein from an mRNA molecule.
What is an anticodon?
An anticodon is a three-nucleotide sequence in tRNA that is complementary to a codon in mRNA.
What is mRNA (messenger RNA)?
mRNA (messenger RNA) is an RNA molecule that carries the genetic information from DNA to the ribosome for protein synthesis.
What is tRNA (transfer RNA)?
tRNA (transfer RNA) is an RNA molecule that carries amino acids to the ribosome during protein synthesis.
What is the reading frame - start and stop codons?
The reading frame is the sequence of codons in mRNA that determines the amino acid sequence of a protein; defined by start and stop codons.
What is a gene?
A gene is a basic unit of heredity; a sequence of DNA that codes for a specific protein or functional RNA molecule.
What is methemoglobin?
Methemoglobin is a form of hemoglobin where the iron is in the ferric (Fe3+) state, which prevents it from binding oxygen properly.
What is hemoglobin?
Hemoglobin is an iron-containing protein in red blood cells that carries oxygen from the lungs to the tissues and returns carbon dioxide from the tissues to the lungs.
What is diaphorase?
Diaphorase is a group of enzymes that help convert methemoglobin back to hemoglobin by reducing the ferric iron (Fe3+) to ferrous iron (Fe2+).
What is the definition of genotype?
Genotype is the specific pairing of alleles for a trait.
What is the definition of phenotype?
Phenotype is the observable expression of a trait.
What is the focus of genotype?
Genotype focuses on genetic makeup (e.g., Big B, little b).
What is the focus of phenotype?
Phenotype focuses on physical or functional appearance (e.g., blue eyes).
How is genotype expressed?
Genotype does not show the trait’s appearance, only the genetic code.
How is phenotype expressed?
Phenotype shows how the trait looks or functions.
What is an example of genotype?
Big B Big B or Big B little b for eye color.
What is an example of phenotype?
Blue eyes, regardless of the genotype.
What does genotype deal with?
Genotype deals with the combination of alleles.
What does phenotype deal with?
Phenotype deals with the trait’s physical expression.
The Law of Segregation
Two alleles of a gene are separated during meiosis and end up in different gametes(sex cells )
The Law of Independent Assortment
During Meiosis, the two alleles of any given gene segregate independently of any two alleles of any other gene
What is a heterozygote?
A heterozygote is an individual with two different alleles for a particular gene.
What is phenotype?
Phenotype is the observable characteristics or traits of an organism, resulting from the interaction of its genotype and environment.
What are alleles?
Alleles are different versions of a gene.
What is a trait?
A trait is a specific characteristic or feature of an organism.
What does phenotypic mean?
Phenotypic relates to or is determined by the phenotype.
What is incomplete dominance?
Incomplete dominance is when neither allele is completely dominant, and the heterozygote displays a phenotype intermediate between the homozygous phenotypes.
What is codominance?
Codominance is when both alleles are fully expressed in the heterozygote, and the heterozygote displays characteristics of both homozygous phenotypes.
What is a complex trait?
A complex trait is influenced by multiple genes and environmental factors, often showing continuous variation (e.g., height, weight, intelligence).
What is pleiotropy?
Pleiotropy is when a single gene affects multiple seemingly unrelated phenotypic traits.
What is a polygenic trait?
A polygenic trait is a trait controlled by multiple genes, often showing continuous variation.
What is epistasis?
Epistasis is the interaction between genes where one gene masks or modifies the expression of another gene.
What is a sex-linked trait?
A sex-linked trait is determined by a gene located on a sex chromosome (usually the X chromosome in mammals), where males need one copy and females need two copies to express the trait.
What is an invariant trait?
An invariant trait is a characteristic that remains essentially unchanged across all individuals within a species or population.
What is a variant trait?
A variant trait is a characteristic that shows variation among individuals within a species or population.
What is a chromatid?
A chromatid is one of two identical copies of a chromosome, joined at the centromere.
What is a centromere?
A centromere is the specialized region of a chromosome where the two sister chromatids are joined and where spindle fibers attach during cell division.
What is a telomere?
A telomere is the protective cap at the ends of linear chromosomes that prevents degradation and fusion.
What is chromatin?
Chromatin is the complex of DNA and proteins (histones) that makes up chromosomes and allows for compact packaging of DNA within the nucleus.
Meiosis I:
Chromosomes duplicate and pair up. In Prophase I, they exchange genetic material through crossing over, creating variation. Then, in Metaphase I, the chromosomes align randomly, and in Anaphase I, they separate. This results in two daughter cells with half the original genetic material.
Meiosis II:
This phase is similar to mitosis. The two daughter cells fromMeiosis I divide again, separating sister chromatids (Prophase II, MetaphaseII, Anaphase II, Telophase II), producing four unique haploid cells.
