MCB 181R Exam 1 Practice Flashcards

A comprehensive set of practice questions and answers based on the MCB 181R Exam 1 transcript, covering cell biology, the endomembrane system, cytoskeleton, meiosis, and Mendelian genetics.

Are prokaryotic chromosomes made of chromatin and packaged with histone proteins?

False.

What is the function of the Golgi apparatus in the endomembrane system?

The Golgi apparatus is involved in processing proteins, including post-translational modifications such as the addition of carbohydrates.

How are homologous chromosomes accurately described regarding their genes and alleles?

Homologous chromosomes typically have the same set of genes but likely have different alleles.

What occurs during Prometaphase I of meiosis?

Microtubules attach to the kinetochores at the centromeres of homologous chromosomes.

Which cellular component is the primary site of lipid synthesis?

The smooth endoplasmic reticulum.

What is the relationship between the genetic information of two sister chromatids?

Sister chromatids have identical genetic information.

If two individuals are heterozygous for an autosomal dominant trait, what is the probability that their offspring will display the dominant phenotype?

$$75\%$$

Which inheritance pattern is characterized by a trait appearing only in males, being passed from an affected father to all his sons, and never appearing in daughters?

Y-linked inheritance.

If a couple has genotypes $AA$ and $Aa$, what is the probability that their offspring will be homozygous for the recessive allele ($aa$)?

$$0\%$$

What are the primary functions of microtubules in a cell?

They are involved in vesicle transport and chromosome movement.

What roles do actin filaments (microfilaments) play in cellular processes?

They play a key role in cell motility, cell shape, and cytokinesis.

How does ploidy change during the processes of mitosis and meiosis?

In meiosis it goes from diploid to haploid, whereas mitosis results in daughter cells with the same number of chromosomes as the parent cell.

What is the difference between Mendel's law of segregation and the law of independent assortment?

Segregation states that two alleles from a single gene separate during gamete formation, while independent assortment says that inheritance of one trait does not affect inheritance of another trait.

Describe the inheritance pattern where all daughters of an affected male are affected, but none of his sons are affected (given the mother is unaffected).

X-linked dominant.

Which cellular structures are found in both prokaryotic and eukaryotic cells?

Cell membrane, cytoskeletal elements, and ribosomes.

What does nondisjunction refer to during cell division?

Nondisjunction occurs when sister chromatids (or homologous chromosomes) fail to separate during cell division.

In plant cells, which cytoskeletal elements form tracks for motor proteins to transport materials?

Microtubules (Note: while intermediate filaments were mentioned in a 'False' question, the transcript highlights microtubules and actin for motion).

Why does the separation of homologous chromosomes during meiosis reduce ploidy?

It distributes one chromosome from each homologous pair into different daughter cells, resulting in haploid gametes.