AP Bio Unit 4 Review Flashcards

Questions and Answers

In what form is DNA loose non-condensed and condensed and organized?

non-condensed=chromatin; condensed=chromosome

2 gametes combine to form a _____. What are the 2 gametes?

zygote; sperm and egg

What occurs during anaphase?

sister chromatids separate

What happens when a cell undergoes mitosis but not cytokinesis?

the cell has 2 nuclei Signup and view all the answers

Following (but not including) which phase of the cell cycle do we have 2 sister chromatids?

S phase Signup and view all the answers

What is the protein involved in passing cell cycle checkpoints that cycles in concentration?

cyclin Signup and view all the answers

What occurs during the S phase?

DNA synthesis Signup and view all the answers

Mitosis produces what kinds of daughter cells?

2 genetically identical cells with 46 chromosomes Signup and view all the answers

Which checkpoint in the cell cycle is considered the restriction point?

G1 checkpoint Signup and view all the answers

When do chromosomes first become visible in mitosis?

prophase Signup and view all the answers

In both mitosis and meiosis, sister chromatids separate during anaphase, but there are _ haploid daughter nuclei produced by meiosis compared to __ diploid nuclei by mitosis.

4; 2 Signup and view all the answers

What is the period in the cell cycle between divisions?

interphase Signup and view all the answers

When does the nuclear envelope disappear in mitosis?

prophase Signup and view all the answers

Meiosis reduces _. Fertilization restores _.

chromosome number Signup and view all the answers

Once mitosis is complete what is the next step?

cytokinesis Signup and view all the answers

When does crossing over occur in meiosis?

Prophase I Signup and view all the answers

What is a protein that aids in adding a phosphate?

protein kinase Signup and view all the answers

Tetrads of chromosomes are lined up at the equator during which stage of meiosis?

Metaphase I Signup and view all the answers

Where do chromosomes become visible in meiosis?

Prophase I and II Signup and view all the answers

At what stage do chromatids separate in meiosis?

Anaphase II Signup and view all the answers

What kinds of cells are typically in G0?

Nerve, muscle, and liver cells Signup and view all the answers

What is PDGF? What is its purpose?

platelet derived growth factor; stimulates cell division to heal Signup and view all the answers

What connects sister chromatids together?

centromere Signup and view all the answers

How long is the cell cycle of an embryo?

20 minutes Signup and view all the answers

If a cell has 40 chromatids at metaphase, how many chromosomes will each daughter cell have after cytokinesis?

20 Signup and view all the answers

How long is the cell cycle for skin cells?

12-24 hours Signup and view all the answers

In mitosis, which stage do we separate out sister chromatids?

Anaphase Signup and view all the answers

If there are 30 chromatids in a cell, how many centromeres will there be?

15 Signup and view all the answers

What is density dependent inhibition?

when cells become overcrowded, they stop dividing Signup and view all the answers

What protein is maintained at constant levels and interacts with cyclin?

cyclin dependent kinases Signup and view all the answers

What are proto-oncogenes?

divide normally, but when mutated they become oncogenes (cancerous cells) Signup and view all the answers

Non-dividing cells are in which stage of the cell cycle?

G0 Signup and view all the answers

What happens during a synapse in meiosis?

homologous chromosomes come together Signup and view all the answers

What is anchorage dependence?

cell must be anchored to something in order to divide Signup and view all the answers

Interphase is composed of which stages of the cell cycle?

G1, S, G2 Signup and view all the answers

What is p53? Name one specific role of this gene.

tumor repressor gene; 3 roles: recruit repair enzymes to repair DNA, triggers apoptosis, and keeps cells in G0 phase Signup and view all the answers

What is the goal of meiosis II? To separate what?

separate sister chromatids Signup and view all the answers

What is the difference between cytokinesis of animals vs. plant cells?

plant cells form cell plate, animal cells form cleavage furrow Signup and view all the answers

Study Notes

Cell Structure and Function

DNA exists in two forms: chromatin (non-condensed) and chromosomes (condensed).
Sister chromatids are connected by a centromere.

Gamete Formation

Two gametes (sperm and egg) unite to create a zygote.

Cell Cycle Phases

Anaphase involves the separation of sister chromatids.
Mitosis without cytokinesis results in a cell with two nuclei.
The S phase is when DNA synthesis occurs, producing two sister chromatids.
Following the S phase, the cell has two sister chromatids.
Interphase is the period between cell divisions, consisting of G1, S, and G2 phases.

Mitosis and Meiosis Comparisons

Mitosis results in two genetically identical diploid daughter cells (46 chromosomes).
Meiosis yields four haploid daughter nuclei, reducing chromosome number.
Crossing over, a key process in meiosis, occurs during Prophase I.
Tetrads align at the equator during Metaphase I of meiosis.

Cellular Checkpoints and Proteins

The G1 checkpoint is referred to as the restriction point in the cell cycle.
Cyclin regulates cell cycle checkpoints, varying in concentration based on cell cycle stages.
Cyclin-dependent kinases maintain constant levels and work alongside cyclins.
p53 is a tumor suppressor gene that recruits repair enzymes, triggers apoptosis, and holds cells in the G0 phase.

Mitosis and Meiosis Processes

Chromosomes first become visible during prophase (mitosis and meiosis).
Cytokinesis follows mitosis, completing the cell division process.
Anaphase is the stage where chromatids separate during both mitosis and meiosis (specifically Anaphase II in meiosis).

Special Cell Conditions

Non-dividing cells are found in G0 phase, often including nerve, muscle, and liver cells.
Density-dependent inhibition stops cell division when cell overcrowding occurs.
Anchorage dependence requires cells to be anchored for division to occur.

Time Frames in Cell Division

The cell cycle duration for embryos is approximately 20 minutes.
Skin cell cycles last between 12-24 hours.
If a cell has 40 chromatids at metaphase, each daughter cell will possess 20 chromosomes.
For a cell with 30 chromatids, there will be 15 centromeres.

Genetic Concepts

Proto-oncogenes normally regulate cell division but can become oncogenes (cancerous) when mutated.
During synapsis in meiosis, homologous chromosomes come together for genetic recombination.
Meiosis I's objective is to separate homologous chromosomes, while Meiosis II's goal is to separate sister chromatids.

Cytokinesis Differences

In animal cells, cytokinesis forms a cleavage furrow, while in plant cells, a cell plate is established.

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Description

Test your knowledge with these flashcards on AP Biology Unit 4. This quiz covers key concepts like DNA structure, gamete formation, and stages of mitosis. Perfect for reviewing before exams and reinforcing your understanding of core biological principles.