Intro to Cell and Molec Exam 4 Rhea

In general, signal transduction via cascading phosphorylation of a series of proteins

brings a conformational change to each protein and, consequently, the activation or inactivation of each protein's function.

Compared to females, males are more often affected by X-linked disorders because

males are hemizygous for genes on the X chromosome.

Compared to asexual reproduction, what advantage does sexual reproduction offer in natural selection?

Sexual reproduction results in many new gene combinations, some of which will lead to differential reproductive success.

Testosterone and other steroid hormones function inside a cell by

binding soluble receptors that enter the nucleus and act as transcription factors.

Which of the following is true for flagella in both prokaryotes and eukaryotes?

IDKKK (both are used for locomotion/movement, both extend from the cell surface)

Which of these statements regarding sexual reproduction and sex chromosomes is true?

All of these answers are true

Which component of the cytoskeleton has the smallest cross-sectional diameter?

Actin filaments

When GPCR's bind their ligand (signalling molecule) they activate G-proteins by

facilitating the exchange of GDP for GTP at the G-protein alpha subunit.

Most signal transduction pathways have multiple steps; which of the following explains why this is advantageous (i.e., why did signal transduction pathways evolve this way)?

Multiple steps allows for amplification, modulation, and integration of signals.

The GTP cap of a microtubule can be described as

the buffer zone of GTP-bound tubulin dimers at the growing end of a microtubule.

Adenylate cyclase synthesizes cAMP; this enzyme has the opposite effect of which of the following?

Phosphodiesterase

What is the second messenger of this signal transduction pathway?

IDKKKK (usually cAMP, IP3, calcium ions, DAG)

The cortex of a cell can be described as

the region where actin filaments are numerous between the plasma membrane and the deeper parts of the cell

An inhibitor of which of the following could be used to block the release of calcium from the endoplasmic reticulum?

IDKKKK

phospholipase C

Wnt signaling is

responsible for maintaining stem cell proliferation

Recombination between linked genes comes about for what reason?

Crossover occurs at a point between these genes during synapsis

Cells that are differentiated and are no longer replicating are said to be in what phase of the cell cycle?

Go phase

Which of the following proteins is an example of a tumor suppressor gene?

DNA repair enzymes

When a neurotransmitter binds to a neuron's receptors and initiats a cascade of relay protein activation that ultimately results in a change to the membrane potential of the neuron (eg the opening of GRIK channels), the neurotransmitter is said to be serving as which of the signal pathway?

First messenger

Which of the following is charecterized by a cell releasing a signal molecule into the environment, followed by a number of cells in the immediate vicinity responding?

Paracrine signaling

The centromere is the region of a chromosome where

sister chromatids remain attached to one another until anaphase.

Testosternone and other steroid hormones function inside a cell by

binding soluble receptors that enter the nucles and act as transcription factors

Regarding synapsism a chromosomal tetrad is composed of which of the following sets of DNA strands?

Two homologous chromosomes composed of two sister chromatids

Which of the following is true regarding receptor tyrosine kinases (RTK's)

IDKKKKKKKKK

(not Many cancers are associated with over expression of RTK's...)

All types of muscle tissue have

IDKKKKKK

maybe:

interactions between actin and myosin, ability to contract, muscle cells with a plasma membrane

Which of the following is true for both the X and Y chromosomes?

None of these answers are true for both X and Y chromosomes

How might a proto oncogene become an oncogene?

IDKKKKK

(not mutation in the proto oncogene's sequence that increases its activity

Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. What does this suggest?

: That the parents were both heterozygous for a single trait

Which of these statements regarding sexual reproduction is true?

All of these answers are true

Which of the following occurs in meiosis but not in mitosis?

Synapsis of chromosomes

What is the relationship between cyclins and Cdks?

Cyclins are regulatory proteins that activate Cdks so they can initiate events in the cell cycle.

Which of the following is the eukaryotic cytoskeletal component at the core of cilia and flagella?

Microtubules

Glycosaminoglycans (GAGs) and proteoglycans

All of these answers are correct

How is natural selection related to sexual reproduction as opposed to asexual reproduction?

Sexual reproduction results in many new gene combinations, some of which will lead to differential reproductive success.

Wnt signaling is

responsible for maintaining cell proliferation.

Males are more often affected by sex-linked traits than females because

None of these answers are correct

Which of the major categories of receptors in the plasma membrane reacts to signaling molecules by forming receptor dimers, undergoing auto-phosphorylation, and then activating relay proteins?

Receptor tyrosine kinases

Which of the following is true for the signaling system in an animal cell that lacks the ability to produce GTP?

IDK: (It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane)

Which of the following statements describes proto-oncogenes?

IDK: They can code for proteins associated with normal cell growth (can become oncogenes when mutated, involved in regulating the cell cycle)

Which of the following epithelium has the shortest diffusion distance?

IDK: simple squamous epithelium

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

IDK: Each diploid cell has eight homologous pairs of chromosomes.

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through

IDK: gap junctions

Which of the following is true for precursor cells?

Precursor cells proliferate and then terminally differentiate to build new tissues during development.

For the alveoli of lungs, having the shortest distance possible for gases to diffuse between air and the blood is critical. Considering this, what type of epithelium (i.e., epithelial cell arrangement) would be present at this interface?

Simple squamous epithelium

Where do the microtubules of the mitotic spindle originate during mitosis?

Centrosome

After telophase I of meiosis, the chromosomal makeup of each daughter cell is

haploid, and the chromosomes are each composed of two chromatids.

In regards to signal transduction, what are scaffolding proteins?

IDKKKK

specialized, non-catalytic adaptor proteins that bind multiple signaling components—such as enzymes, kinases, and receptors—together into a single, localized complex.

Use the figure shown above, indicate which grouping represents a set of sister chromatids.

Group A

Two plants with yellow flowers are crossed, resulting in offspring in which 75% have yellow flowers and 25 have white flowers. What does this suggest?

The parents were both heterozygous for the flower-color gene.

Using the figure shown above, indicate which grouping represents a set of sister chromatids.

A

What is the phenomenon that occurs when the rate of an actin subunits attaching to the plus end of an

Treadmilling

If a cell has a mutation that prevents it from making a protein kinase needed for the M phase checkpoint, which of the following would likely be the result of this mutation?

The cell would undergo normal mitosis but fail to enter the next G1 phase.

Which of the following best describes a karyotype?

A display of each chromosome of a single cell

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