bio study

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the cell

smallest unit of life

Cell theory

1) The cell is the fundamental unit of structure and function in living things.
2) All organisms are made of one or more cells.
3) Cells arise from other cells through cellular division.
4) Cells carry genetic material passed to daughter cells during cellular division
5) All cells are essentially the same in chemical composition
6) Energy flow (metabolism) occurs within cells

matter

is composed of elements;
a substance that cannot be broken down to other substances by chemical reactions

atomic number

The number of protons

Mass number

# of protons + neutrons

isotopes

differ in their number of neutrons

Energy

the capacity to cause change, or do work

reactivity

# electrons in valence shell

ionic

one atom donates one or more electrons; one atom gains one or more electrons

Covalent

two atoms share a pair of electrons

Weak chemical bonds

-Hydrogen bonds
• van der Waals interactions

Hydrogen bonds

weak interaction between the δ+ charge of a hydrogen atom from one molecule and the δ- charge of a more electronegative atom.

van der Waals

transient regions of polarity that become attractive and can induce polarity in neighboring molecules.

"emergent properties" of H2O

1. Cohesive/adhesive
2. Moderates temperature
3. Ice less dense than liquid water
4. Excellent solvent

cohesion

water sticks to itself

adhesion

water sticks to other things

Thermal energy:

kinetic energy associated with movement of atoms and molecules

Temperature:

measurement of kinetic energy in a body of matter

Heat

thermal energy in transfer; is measured in calories and joules

Water has a

high specific heat capacity

specific heat capacity:

amount of heat required to raise 1g by 1°C
for water, this is 1 calorie per gram of water per 1°C, or 4.18 Joules per gram of water per 1°C.

Water is ___________ when it is frozen

less dense

Adhesion of water:

Water sticks to any surface that is polar or has exposed nitrogens or oxygens. interaction with other molecules

water is a polar solvent:

It dissolves polar substances, also called hydrophilic

hydrophilic

water loving

Longer organic (carbon-containing) compounds are

less miscible

Miscible

liquids are liquids which are able to mix.

Immiscible

liquids are liquids which are unable to mix.

Substances that repel water (not miscible) are said to be

hydrophobic

molar

amount of dissolved substance per liter of solution

Folic acid and vitamin C are important ___________ that we usually obtain from the food we eat.

Coenzymes

Which of the following are properties of liquid water? Check all that apply.

Liquid water has a specific heat that is higher than that for most other substances.

Liquid water can dissolve ionically bonded compounds like NaCl.

Liquid water consists of molecules that are nonpolar.

The H+ concentration inside of a lysosome in your cell is 1.0 x 10-3. The lysosome maintains this concentration through active transport of H+ from the cytosol to the interior of the lysosome. An inhibitor of the H+ transport protein gets into the cell and blocks it from transporting H+ into the lysosome. Within 30 minutes, the pH of the lysosome lumen rises by 2 pH units. What is the resulting concentration of hydroxide (OH-) ions?

1.0 x 10-9

For living organisms, which of the following is an important consequence of the first law of thermodynamics?

The organism ultimately must obtain all of the necessary energy for life from its environment.

Mitochondria and chloroplasts have their own DNA. The structure of this DNA is similar to what group of free-living organisms?

eubacteria

The Calvin Cycle takes place in the ___A___ .

Stroma

In the first phase of the cycle, the enzyme ___B___ fixes carbon dioxide by joining it to ___C___, a 5-carbon molecule, which quickly forms two molecules of 3-phosphoglycerate.

.
Rubisco, Ribulose 1,5 bisphosphate

After this, ___D___ (energy) and ___E___ (reducing power) from the ____F____ are used to convert 3-phosphoglycerate to ____G____.

ATP, NADPH, Light-dependent reactions, Glyceraldehyde-3-phosphate

For every three "turns" of the Calvin cycle, one molecule of ___G___ goes toward producing ___H___ and five are used to regenerate ___C___.

Glyceraldehyde-3-phosphate, Glucose, Ribulose 1,5 bisphosphate

You want to study what happens when you knock out the glycolysis pathway in the cell. Which substance would allow you to do this?

A chemical that mimics the structure of glucose, but can't be fully metabolized

In the BIOL 005A laboratory, you are growing a culture of yeast to study how feeding the yeast different compounds affects cellular respiration. If you add citric acid to the medium that the yeast uses to get nutrients, what will happen to the rates of carbon dioxide and ATP production?

The yeast would produce both ATP and carbon dioxide at higher rates

_____A_____ like glucose are not the only molecules that feed into cellular respiration.

.
Carbohydrates

____B____ can be broken down to yield _____C_____, acetyl CoA, and intermediates in the _____D______.

Amino acids, Pyruvate, Citric acid cycle

Before being converted to these molecules, the _____E_____ must be removed from _____B_____ and converted to ammonia for excretion.

Amino group, Amino acids

_____F_____ are the most energy-rich molecules.

Triglycerides

Breakdown of ____F____ produces ____G_____ and oxidation of the C-H rich "tails" produces _____H_____.

Triglycerides, Glycerol, Acetyl CoA

_____G_____ can be easily converted to glyceraldehyde-3-phosphate to feed into _____I_____, while ____H____ can feed into the _____D_____.

Glycerol, Glycolysis, Acetyl CoA, Citric acid cycle

In the process of glycolysis, for each molecule of glucose that is converted to pyruvate, ____________.

Two molecules of ATP are used and four molecules of ATP are produced

You see a bear while on a hike and release epinephrine. Within seconds, you have enough glucose-1-phosphate to run back down the trail to safety (or to fight the bear, your choice).

Signal amplification

Two plant cells living next to each other can exchange cytoplasm

Plasmodesmata

A peptide hormone travels in the bloodstream and triggers a response only in kidney cells

Endocrine signaling

A scientist tests a potential anti-SARS-CoV-2 drug on a cell culture and notices a large increase in cyclic AMP concentration after the drug is applied.

Second messenger

A hormone binds to a cell surface receptor. Analysis of the cells immediately after this event finds that three new protein kinases are in the "active" state, while the ATP concentration has dropped and the ADP concentration has gone up

Phosphorylation cascade

Analysis of gene expression in tumor cells finds that six different processes are disrupted. External addition of a hormone regulating these processes to a culture of the cells also doesn't trigger them. What structure could be functioning abnormally?

Receptor tyrosine kinase

A signaling molecule binds to a receptor and the concentration of GTP in the cytoplasm goes down.

G protein-coupled receptor

You touch a hot stove and your brain registers this immediately, instead of 2 minutes later when your burn would be much worse. What receptors make this possible?

Ion channel receptors

Think about plants that use C3 photosynthesis (e.g., lettuce) to those that use C4 photosynthesis (e.g., maize). Compared to lettuce, maize will _______.

Keep fixing CO2 even at lower CO2 concentrations and higher O2 concentrations

DNA is isolated from bacteria undergoing DNA replication. After heat treatment to disrupt H-bonds the DNA is centrifuged and it separates into two classes. One class of DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). Which types of DNA do the two classes most likely represent?

leading strands and Okazaki fragments

The sequence of nucleotides below is present at a DNA location where the chain opens to form a replication fork:
3' C C T A G G C T G C A A T C C 5'
An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

5' A C G U U A G G 3'

Hershey and Chase set out to determine which type of molecule is used for genetic inheritance. They completed a series of experiments where E. coli was infected by a T2 virus. Which molecular component of the T2 virus ended up inside the cell?

DNA

Which of the following events would be most likely to produce cells with several nuclei

repeated mitosis without cytokinesis

In a diploid cell with four chromosome pairs (2n = 8), how many sister chromatids will be found in a nucleus at prophase of mitosis?

16

Movement of the chromosomes during anaphase would be most directly affected by a drug that prevents which of the following events?

shortening of microtubules

The mass of DNA per nucleus in a certain fungus ranges from 4 to 10 picograms. Nuclei with 5 picograms of DNA are most likely derived from cells in which of the following parts of the cell cycle?

G1

In which phase of mitosis do the sister chromatids become daughter chromosomes?

anaphase

Quaking aspen trees usually reproduce by extending underground stems that then push aboveground and grow into trees. Sexual reproduction is not as common, but when it does happen, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems?

38

Which of the following statements is true of a species that has a chromosome number of 2n = 16?

Each diploid cell has eight homologous pairs of chromosomes.

A cell has completed meiosis I and the first cytokinesis, and is just beginning meiosis II. Which of the following statements describes its genetic contents?

It has half the amount of DNA as the cell that began meiosis.

Which of the following sentences state a significant conclusion that Gregor Mendel drew from his experiments with pea plants?

Traits are inherited in discrete units and are not the result of "blending."

Which of the following statements about the law of segregation is correct?

It describes the inheritance of different alleles relative to one another.

A diploid animal is dihybrid at the Head shape (H) and Tail length (T) loci. Which of the following gamete genotypes can it produce?

Ht

Mendel crossed true breeding yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6,022 yellow and 2,001 green (8,023 total). Which of the following statements correctly describes the relationship of the allele for green seeds to the allele for yellow seeds?

The green allele is recessive to the yellow allele.

Cinnabar eye color is an X-linked, recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a male having wild-type, red eyes, what percent of the F1 males will have cinnabar eyes?

100%

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients' muscles weaken over time because they have a lack or decreased levels of dystrophin, a muscle protein. Which of the following correctly predicts the probability of muscular dystrophy in female children?

One-half of the daughters of an affected man and a carrier woman would have this condition.

Use this model of a eukaryotic primary transcript to answer the following question.

E = exon and I = intron
5′-UTR E1 I1 E2 I2 E3 I3 E4 UTR-3′

If the primary transcript is processed and transported to the cytosol, which of the following molecules best represents the mRNA that will be produced?

5′-UTR E1 E2 E3 E4 UTR-3′

Which of the following best describes the redundancy in the genetic code?

More than one codon can specify the addition of the same amino acid.

According to the central dogma, which of the following intermediate molecules correctly completes the flow chart describing the flow of information in a cell blank?

DNA → ________ → Proteins

mRNA

Which of the following processes occurs in prokaryotes but not in eukaryotes?

simultaneous transcription and translation of the same mRNA

Which of the following is the most likely phenotypes of a yeast mutant that contains histones that are resistant to acetylation?

The mutant will show decreased levels of gene expression.

Which of the following best explains why a neuron and a pancreatic cell isolated from the same individual contain different sets of proteins?

Each cell type contains different regulatory proteins and, therefore, they express different proteins

Gene expression is often assayed by measuring the level of mRNA produced from a gene. Which of the following levels of the control of gene expression can by analyzed by this type of assay?

transcriptional control

DNA methylation and histone acetylation are examples of which of the following processes?

epigenetic phenomena

Which of the following functions are characteristic of general transcription factors in eukaryotes?

They bind to other proteins or to the TATA box.

What amino acid sequence will be generated based on the following mRNA codon sequence?
5′-AUG-UCU-UCG-UUA-UCC-UUG-3

Met-Ser-Ser-Leu-Ser-Leu

Which of the triplets below is a possible anticodon in a tRNA that transports proline to a ribosome?

3′-GGC-5′

Once researchers identified DNA as the molecule responsible for transmitting heritable traits, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. Which of the following statements correctly describes the mechanism of information transfer that accomplishes this task in eukaryotes?

Messenger RNA is transcribed from a single gene and transfers information to the cytoplasm, where protein synthesis takes place.

Which of the following statements correctly describes a ribozyme?

It is an RNA with catalytic activity.

If a bacteria contained a mutant aminoacyl-tRNA synthetase that attaches a lysine instead of the normal phenylalanine to tRNAs with the anticodon AAA which of the following would occur?

Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU

Which of the following statements is a correct representation of gene density?

Humans have ~20,000 protein-encoding genes in a 3,000 Mb.

Crickets and fruit flies are both insects. Which of the following statements could explain why a certain cricket genome has eleven times as many base pairs as that of the fruit fly, Drosophila melanogaster?

Crickets must have more noncoding DNA.

Which of the following statements explains the observation that the number of different proteins a vertebrate produces may be larger than the number of genes found within their genome?

Vertebrates can produce more than one polypeptide from a single gene.

Which of the following statements correctly describes retrotransposons?

They use an RNA molecule as an intermediate in transposition

A recent study compared the Homo sapiens genome with that of Neanderthals. The results indicated that the two genomes mixed at some period in evolutionary history. Which of the following data would provide additional support for this hypothesis?

DNA from a modern H. sapiens that contains some Neanderthal sequences

Which of the following best explains the presence of homologous genes in different species?

the species descended from a common ancestor

Studies in knockout mice have demonstrated an important role of the FOXP2 transcription factor in the development of vocalizations. Recent sequence comparisons of the FOXP2 gene in Neanderthals and modern humans show that while the DNA sequence may be different, the protein sequence it codes for is identical. Which of the following conclusions might logically be inferred from this information?

Because the FOXP2 protein sequences were identical, human and Neanderthal vocalizations may have been more similar than previously thought.

A piece of DNA was incubated with a restriction enzyme called Hind III. The restriction enzyme digestion produced eight different size fragments that were separated by gel electrophoresis.

When separated by gel electrophoresis, the pattern of DNA bands specific to Hind III digestion; repeating the process using a different restriction enzyme would not produce these fragments.

Which of the following statements describes a technical barrier to using gene therapy in humans?

The expression of transferred genes may not be appropriately controlled.

Which of the following is an ethical question regarding the use of CRISPR-Cas9 gene editing in humans?

Should we be able to select and control the genetic makeup of the human population?

CRISPR/Cas technology is a technology used for:

Gene Editing

Radioactive isotopes were used to track macromolecules by which scientists?

Alfred Hershey and Martha Chase