Exam 1: all topics + past exam questions

What is interphase and what does it include?

Where the cell prepares for division, includes 3 phases: 1. G1 phase = Cell grows, production of organelles and mitochondria 2. S phase = where DNA is duplicated 3. G2 phase = continued growth, completes preparation for cell division. S phase happens only once before either mitosis or meiosis.

What is the chromosome number of the original parent cell in mitosis?

Diploid (2n)

What is the main purpose of mitosis?

Goal is to multiply cells (increase the number of cells) for growth, repair, and maintenance

What happens during prophase in mitosis?

Miotic spindle begins to form and discrete, duplicated chromosomes form

What happens during metaphase in mitosis?

Microtubules attach to all chromosomes, chromosomes line up on the center line

What happens during anaphase in mitosis?

Sister chromatids separate and move towards opposite poles

What happens during telophase in mitosis?

Nuclei reform, chromosomes uncoil, followed by cytokinesis, the cytoplasm divides and the cell fully splits into 2 daughter cells (2 identical diploid (2n) daughter cells)

What is the result product of mitosis?

2 diploid (2n) daughter cells, 100% genetically identical

How much DNA do the daughter cells formed in mitosis share with each other?

They share 100% of their DNA

How much DNA do the daughter cells formed in mitosis share with the original parent cell?

They share 100% of their DNA with the original parent cell, meaning that they are genetically identical to the parent cell

What separates during mitosis, in which phase, and why?

Sister chromatids line up on the center line during metaphase and separate during anaphase of mitosis to ensure that each daughter cell receives an identically and complete set of chromosomes

What is the main purpose of meiosis?

Goal is to create gametes (cells with 1 set of chromosomes) through reducing the number of chromosomes, and in the end, produces 4 genetically unique haploid (n) gametes

What happens during prophase I of meiosis?

Homologous chromosomes pair up (called synapsis) and crossing over occurs (exchange of genetic material, which increases genetic variation)

What happens during metaphase I of meiosis?

Homologous chromosome pairs line up on center line. Independent assortment occurs (segregation of parental chromosomes pairs in random - random assortment leads to genetic variation)

What happens during anaphase I of meiosis?

Homologous chromosomes separate and move to opposite poles which reduces the chromosome number (from diploid to haploid). Sister chromatids stay together, unlike in mitosis.

What happens during telophase I of meiosis?

Includes cytokinesis, allowing 2 haploid cells to form. Nuclear membrane may reform briefly and cells move into Meiosis II without DNA replication.

What separates during meiosis I, in which phase, and why?

The replicated homologous chromosomes are separated during anaphase I of meiosis to reduce the chromosome number (to go from diploid (2n) to haploid (n))

What is independent assortment?

Segregation of parental chromosomes pairs in random because random assortment leads to genetic variation

Which phase of meiosis is similar to mitosis and why?

Meiosis II is similar to mitosis because the sister chromatids also separate

What happens during prophase II of meiosis?

Chromosomes condense, spindle fibres form, and nuclear membrane breaks down

What happens during metaphase II of meiosis?

Chromosomes line up at the center line

What happens during anaphase II of meiosis?

Sister chromatids separate and move to opposite poles

What happens during telophase II of meiosis?

Includes cytokinesis, forming 4 haploid (n) gametes, where each gamete has a unique genetic combination

What separates during meiosis II?

The sister chromatids

What do the steps in Meiosis I and II ensure in terms of genetic make-up of the gametes (relative to the genetic make-up of the parent cell)?

The steps ensure that each gamete produced contains a unique combination of alleles, contributing to genetic diversity in offspring

What is crossing over?

Exchange of genetic materials between paired homologous chromosomes (one from each parent)

When does crossing over happen?

During prophase I of meiosis

What is the goal of crossing over?

To increase genetic diversity

What does it mean if two chromosomes are homologous?

They carry genes that code for the same trait

Which cell structure is not found in a prokaryotic cell?

Nucleus

What happens during cellular respiration?

Cellular respiration consumes O2 and discards CO2

What happens during photosynthesis?

In photosynthesis CO2 is consumed and O2 is released

Where is photosynthesis carried out?

Photosynthesis is carried out in prokaryotic cells within the chloroplasts, chlorophyll

Can plants do cellular respiration?

Plants can do both photosynthesis and also cellular respiration which is in mitochondria

What happens to nuclear DNA in eukaryotic cells?

It never leaves the cell

What is an example of non-nuclear DNA?

Non-nuclear DNA is often inherited uniparentally, meaning that offspring get DNA only from the male or the female parent, not both. In humans, for example, children get mitochondrial DNA from their mother (but not their father).

How is DNA organized?

In chromosomes which carry genes

A male will transmit an X-linked gene to?

All his female offspring

A male will transmit an Y-linked gene to?

All his male offspring

In genetics, dominance

Is defined with respect to a pair of alleles coding for the same trait, with respect to the genotype, and with respect to the phenotype

Do all homologous pairs of chromosomes contain genes coding for the same trait?

Yes, with the exception of the sex chromosomes in males

What do homologous chromosomes mean in terms of their genetics?

They are chromosomes coding for the same gene and trait

What separates during metaphase and anaphase of mitosis?

Sister chromatids, ensures that each have the same from each parent

Why is the separation during metaphase and anaphase of mitosis necessary?

In order for the cell to split into half and form 2 daughter cells from one parent

What separates during Meiosis I?

The replicated homologous chromosomes

What separates during Meiosis II?

Sister chromatids