Biology Of Cell

Question 1

Describe the structure of nucleic acids including base pairing and covalent vs hydrogen bonds.

Answer 1

Each nucleic acid includes Sugar, phosphate, nitrogenous base, hydrogen bond

Question 2

Compare and contrast DNA and RNA structure.

Answer 2

DNA: Made up of nucleotides, Uses Thymine, double-stranded, nucleus only
RNA: Made out of nucleotides, has 2 hydroxyl groups, uses uracil, single-stranded, nucleus and cytoplasm

Question 3

Define the following terms: chromosome, histone, homologous chromosome, centromere, sister chromatid, telomeres, diploid, haploid, gene, genetic locus, allele and genome.

Answer 3

Chromosome: DNA associated with an array of different proteins into a complex structure

Histone: Proteins that compact DNA to fit into the cell

Homologous chromosome: Two versions of each chromosome

Centromere: Where the chromatids get stuck

Sister Chromatid: two identical copies of the same chromosome formed by DNA replication

Telomeres: Protect functional genes from worn-down damage

Diploid: two complete sets of chromosomes

Haploid: Gametes/Sex cells, contain unpair chromosomes

Gene: Specific stretch of DNA that codes for protein

genetic locus: Specific location on the chromosome

Allele: One copy for the opposite of the other

Genome: The complete complement of genetic material in an organism

Question 4

Describe the basic process of DNA replication and how it leads to the creation of identical sister chromatids.

Answer 4

Parents molecules: strands are together and have 1 chromosome and 1 chromatid

Separation of Strands: the parent strands start to separate

Daughter cells: Makes a copy of each strand then gets paired with a new strand “one old and one new”

Question 5

Outline the events of each stage (G1, S, G2, M) of the cell cycle. Indicate which stage the majority of cells are in, when chromosomes replicate (DNA replication), when chromosomes segregate, and when the cell divides.

Answer 5

G1: Active gene expression, Preps DNA synthesis
S: DNA synthesis, creates identical sisters for each chromosome
G2: Prep for Cell Division
M: Cell division

Question 6

Describe what main action happens in each of the following stages of mitosis: Prophase (3 actions), Metaphase, Anaphase and Telophase (3 actions).

Answer 6

Prophase: Dissolves nuclear membrane, co-dense DNA, Mitotic spindle forms

Metaphase: Nuclear membrane reforms, DNA unwinds/deco-dense, Mitotic spindle breaks down

Anaphase/Telophase: Two daughters produce by mitosis

Question 6

Explain the role of meiosis in the diploid life cycle, including the terms gametes, somatic cells, and germ cells.

Answer 6

Meiosis produces haploid gametes from diploid germ cells, which are used in sexual reproduction to form a new diploid organism. Somatic cells are diploid and undergo mitosis for growth and maintenance of the body.

Question 7

Describe the primary similarities and differences between mitosis and meiosis.

Answer 7

Mitosis and meiosis are two types of cell division processes. Mitosis results in two identical daughter cells, while meiosis produces four genetically diverse daughter cells due to chromosome pairing and recombination. Mitosis involves one cell division, while meiosis involves two rounds of cell division. Mitosis is involved in growth, repair, and asexual reproduction, while meiosis is involved in sexual reproduction and creating genetically diverse offspring.

Question 8

Define dominant and recessive phenotypes, and describe how each corresponds with homozygous and/or heterozygous genotypes.

Answer 8

Dominant traits are expressed if an organism inherits one or two copies of the gene responsible for the trait.

Recessive traits are only expressed if an organism inherits two copies of the gene responsible for the trait.

Homozygous dominant and heterozygous genotypes are usually associated with dominant traits, while homozygous recessive genotypes are associated with recessive traits.

Question 9

Identify Huntington’s disease and familial hypercholesterolemia as prevalent autosomal dominant human disorders, and identify cystic fibrosis and sickle cell anemia as prevalent autosomal recessive disorders.

Answer 9

Huntington’s disease and familial hypercholesterolemia are autosomal dominant disorders

Cystic fibrosis and sickle cell anemia are autosomal recessive disorders.

Huntington’s disease affects brain function, familial hypercholesterolemia causes high cholesterol, cystic fibrosis affects the lungs and other organs, and sickle cell anemia causes blood disorders.

Question 10

Define the terms gene expression, transcription, and translation.

Answer 10

Transcription: The process of using a DNA template to make mRNA

Translation: Process of making a polypeptide using mRNA template

Question 11

Explain the basic steps of transcription (initiation, elongation, termination).

Answer 11

Initiation: mRNA and ribosome segments come together. tRNA carrying the first amino acid binds to the start codon

Elongation: Amino acids are carried by tRNA to the mRNA. They create a long polypeptide chain

Termination: The stop codon in mRNA is found by the release factor, a protein, and translation components come apart. This releases the polypeptide chain

Question 12

Explain the basic steps of translation (initiation, elongation, termination).

Answer 12

Initiation: RNA polymerase binds to the promotor region of the gene

Elongation: RNA polymerase slides along the region of the gene that gets transcribed, matching RNA nucleotide to DNA template

Termination: RNA polymerase hits the terminator region of gene and detaches from DNA

Question 13

Explain how the triplet code works. Be able to build an amino acid chain from an mRNA sequence, if given the codon chart.

Answer 13

The bases in mRNA are read in triplets, Start codon is AUG and stops at UAA, UAG, UGA

Question 14

Explain how DNA mutations can arise and describe different types (point, insertion, deletion) of mutations.

Answer 14

Point: Change in a single nucleotide base pair

Insertion: Addition of one or more nucleotides

Deletion: Removal of one or more nucleotide

Question 15

Recognize the role of ATP as the universal energy molecule and that energy is stored in the phosphate bonds of ATP.

Question 16

Explain biological oxidation and reduction in terms of electron and hydrogen/proton transfer, and the role electron carriers play in this process. Be able to identify specific examples of electron carriers used in glucose metabolism.

Answer 16

Oxidation: removal of electrons
Reduction: Addition of electrons

Electron carriers are molecules that accept and donate electrons to shuttle them from one molecule to another

EX: NAD+ = NADH
FAD = FADH2

Question 16

Describe the fate of electrons, original and final carbon molecules, electron carriers, and ATP yield (per glucose molecule) for each of the 5 stages of glucose metabolism including glycolysis, pyruvate oxidation, the TCA cycle, electron transport chain and ATP synthesis.

Answer 16

Glycolysis: Broken down into pyruvate with production of two ATP molecules

Pyruvate oxidation: pyruvate is converted into acetyl- CoA and no ATP is produced

TCA cycle: acetyl-CoA is broken down into CO2 with two ATP production

Electron Transport: Electrons are transferred from electron carriers to electron transport chain and a proton gradient is created

ATP Synthesis: Production of ATP using the energy from the proton gradient created in the electron transport chain

Question 17

Identify the cellular location of each of the 5 stages of glucose metabolism.

Answer 17

Glycolysis: occurs in cytoplasm

Pyruvate: occurs in mitochondria

TCA cycle: occurs in mitochondria

Electron transport: Occurs in inner mitochondrial membrane

ATP Synthesis: occurs in inner mitochondrial membrane

Question 18

Summarize glycolysis in terms of original and final carbon molecules, and net ATP and NADH production.

Answer 18

Glycolysis is the first stage of glucose metabolism. It breaks down glucose into two molecules of pyruvate, producing a net of two ATP molecules per glucose molecule and two molecules of NADH. The original carbon molecules from glucose are converted into pyruvate, a three-carbon molecule. Glycolysis is a key process in energy production.

Question 19

Explain what fermentation is, why fermentation is not ideal but aerobic respiration is for many cells, and identify the role of oxygen in this process. Provide examples of cell types that utilize fermentation versus aerobic respiration.

Answer 19

Fermentation is an anaerobic process that allows cells to produce energy in the absence of oxygen. However, it is not ideal for many cells because it produces only a small amount of ATP and wastes products that can be toxic to cells. In contrast, aerobic respiration produces much more ATP through the TCA cycle and electron transport chain and requires oxygen as the final electron acceptor. Examples of cells that use fermentation include bacteria, yeast, and muscle cells during intense exercise.

Question 20

Explain the general function of the electron transport chain.

Answer 20

The electron transport chain transfers electrons from electron carriers to a series of proteins in the inner mitochondrial membrane. This creates a proton gradient that drives ATP synthesis through oxidative phosphorylation. The regulation of this process is crucial for cellular metabolism and function.

Question 21

Generally describe how ATP synthase works.

Answer 21

ATP synthase is a protein complex in the inner mitochondrial membrane that uses the energy from a proton gradient to synthesize ATP from ADP and inorganic phosphate. It works by causing conformational changes in the protein complex, which drive the rotation of a central rotor and the synthesis of ATP. ATP synthase is highly efficient and regulated by the proton gradient created by the electron transport chain and oxidative phosphorylation.

Question 22

What is Prophase

Answer 22

Centrioles have moved apart and the nuclear membrane starts to disappear

Question 23

What is Prometaphase

Answer 23

Centrioles are at opposing ends and the nuclear membrane is nearly gone

Question 24

What is Metaphase

Answer 24

Spindle fibers are attached to the chromosomes centromeres and they line up in the middle of the cell

Question 24

DNA turns to mRNA by

Answer 24

Transcription

Question 24

What us Anaphase

Answer 24

The centromeres split and move to apposite sides of the cell

Question 25

If a heterozygous colorful chameleon was crossed with a homozygous-recessive colorful chameleon, what would be the genotype and phenotype of all potential offspring? What are the genotypes and phenotypes of the parents?

Answer 25

Bb, bb, Bb, bb
Parents (hetero: Bb, Homo: bb)
Offspring: 1/2 homo and 1/2 hetero

Question 25

mRNA turn to protein by

Answer 25

Translation

Question 25

What is Telophase

Answer 25

The cell membranes complete building, the nuclear membrane forms around chromosomes, and the cells form daughter cells

Question 26

Scientists have discovered that there is a dominant trait (H) on the X chromosome (a sex-linked trait) that tells us someone will have long hair. Ben (a biological male) has always been able to grow super long hair, however, his wife Anna (a biological female) has always had super short hair. What are the possible genotypes and phenotypes of their offspring? What are the genotypes of Ben and Anna?

Answer 26

XHXh, XhY, XHXh, XhY
Ben: x^h y (long hair, must have “H” trait)
Anna: x^h x^h (short hair, cannot have “H” trait)
All their daughters will have long hair (x^ H, x^h), all their sons will have short hair (x^h y)

Question 26

True or False: Point mutations are when there is any change or mutation in the DNA.

Answer 26

True

Question 27

TRUE OR FALSE: Silent mutations have the same base and code for the correct amino acid.

Answer 27

False

Question 27

describe the triplet code?

Answer 27

mRNA or a chain of base pairs is read. Each three is the instruction for an amino acid. These 3 bases are identified as codons, one codon is one amino acid. Multiple amino acids make proteins(translation)

Question 28

TRUE OR FALSE: During deletion, base pairs are added.

Answer 28

False

Question 28

TRUE OR FALSE: During insertion, base pairs are deleted.

Answer 28

False