Chapter 12, 13 Cell Cycle Lecture Flashcards
Cell Theory (Recap):
Cells are the basic unit of life.
All living organisms are made of one or more cells.
Cells come from pre-existing cells (focus of this unit).
Cell Reproduction allows:
enabling growth (more cells)
offspring creation.
Three Main Types of Cell Reproduction
Eukaryotes: Mitosis,Meiosis
Prokaryotes: Binary Fission
_______ (Prokaryotes):
Process: Similar to mitosis but distinct due to prokaryotic structure; one cell divides into two identical cells.
Purpose: Increases population (e.g., bacterial growth).
Outcome: Clones, like mitosis, but structurally simpler.
Binary Fission
______(Eukaryotes):
Process: One cell divides to produce two identical daughter cells.
Purpose:
Multicellular Eukaryotes: Replaces worn-out cells, increases somatic (body, non-reproductive) cell number for growth (e.g., human development from one cell to trillions).
Unicellular Eukaryotes: Reproduces the organism (e.g., yeast, a single-celled fungus, splits into two identical individuals via mitosis + cytokinesis).
Outcome: Identical clones.
Mitosis
_______ (Eukaryotes):
Process: One cell undergoes two divisions and DNA recombination, producing four non-identical cells.
Purpose: Creates gametes (reproductive cells, e.g., sperm, eggs) with increased genetic diversity.
Outcome: Four unique cells, unlike the original or each other.
Meiosis
Eukaryotic Cell Cycle
Two Main Phases
- Interphase
2, Mitosis and Cytokinesis
All the DNA in an organism or a specific cell.
genome
the complete genetic “blueprint”—varies by context (whole organism vs. single cell).
genome
A DNA-protein complex found in the nucleus (not nucleolus) of eukaryotic cells.
Chromatin
DNA double helix winds around histone proteins, looking “noodle-like” but organized.
Chromatin
Chromatin’s structure prevents tangling, like yarn wound on a spool.
______ are proteins that DNA wraps around, organizing chromatin and preventing tangling.
Histones
DNA coils around _____ “spheres,” keeping it structured, like winding yarn to avoid knots.
histones helping chromatin
Condensed packages of chromatin containing genes, formed when chromatin coils during the cell cycle.
Chromosomes
In interphase, DNA is loose (______); during mitosis/meiosis, it condenses into discrete units (______) for division.
chromatin
chromosomes
The “packed” form of DNA, making it easier to move during cell division.
Chromosomes
Identical copies of a chromosome, formed after replication, joined at the centromere.
sister chromatids
During __ phase, a chromosome duplicates (e.g., chromosome 1 becomes two sister chromatids), looking like an “X” with a centromere in the middle.
S
They’re twins of the same chromosome, not from different parents—key for mitosis/meiosis.
Sister chromatids
A DNA region holding sister chromatids together until division.
centromere
Central structure on the chromosome where microtubules attach during mitosis/meiosis to pull chromatids apart.
centeromere
the “glue” or “handle” for chromosome movement.
centeromere
A pair of chromosomes (one from mom, one from dad) with the same genes but possibly different alleles.
homologous chromosomes
chromosome 1 from mom (purple) and dad (blue) both have hair color genes, but alleles might differ (brown vs. blonde). Humans have 23 pairs (46 total).
homologous chromosomes
They’re like “matching sets” from parents, not identical copies.
homologous chromosomes
During the_ phase of the cell cycle, when___ ____, homologous chromosomes form sister chromatids.
During the S phase of the cell cycle, when DNA replicates homologous chromosomes form sister chromatids.
During the __ phase of the cell cycle, Each homologous chromosome (e.g., mom’s chromosome 1, dad’s chromosome 1) copies itself, forming two _____ ______per chromosome (four total for the pair).
S phase
sister chromatids
A picture of an organism’s chromosomes, arranged in pairs
karyotype
(e.g., human karyotype shows 23 pairs, 46 total).
chromosome number and structure—humans always have – (– pairs).
46
23
____ _____ (e.g., purple from mom, blue from dad) with ______ _______ post-replication.
homologous chromosomes (e.g., purple from mom, blue from dad) with sister chromatids post-replication.
*_________ are identical copies of one chromosome (e.g., two chromosome 1s from mom post-replication).
*________ are a pair from different parents (mom’s 1 vs. dad’s 1) with the same genes but different alleles.
Sister chromatids
Homologous chromosomes
Nucleolus is a nucleus subregion for ribosome assembly, not all chromatin.
Nucleolus is a nucleus subregion for ribosome assembly, not all chromatin.
Why does chromatin condense into chromosomes?
To organize and move DNA efficiently during cell division (mitosis/meiosis).
Loose _____ in interphase condenses in prophase into compact _____ for separation into daughter cells.
chromatin
chromosomes
Do homologous chromosomes form during replication?
No
Details: Homologous chromosomes exist from birth (one from mom, one from dad). Replication (S phase) forms sister chromatids from each homologous chromosome, not the pair itself.
How do sister chromatids and homologous chromosomes relate in a karyotype?
A karyotype shows 23 homologous pairs (e.g., mom’s 1, dad’s 1); post-S phase, each has sister chromatids (e.g., two mom’s 1s, two dad’s 1s).
Genome/Chromatin (_______), Chromosomes/Sister Chromatids (_____), Homologous/Karyotype (_____).
DNA organization
division prep
inheritance
Mitosis Roles: _____ (multicellular), _____ (unicellular eukaryotes).
Growth (multicellular), reproduction (unicellular eukaryotes).
Cell Cycle Phases:
Interphase (G1, S, G2) prepares; Mitosis + Cytokinesis divides.
Cell Division: process of a single (parent) cell dividing or splitting into ≥ 2 “______________________” cells.
daughter
______________ Fission: _____________________ cell division.
Binary Fission: Prokaryotic cell division.
________________: eukaryotic cell division producing ______________ cells (body cells).
□ Human somatic cells are ________________ (2n) since they have _____ copies of every chromosome.
Mitosis: Eukaryotic cell division producing somatic cells (body cells).
□ Human somatic cells are diploid (2n) since they have 2 copies of every chromosome.
________________: eukaryotic cell division producing _______________ (sex cells).
□ Human gametes are ________________ (n) since they have _____ copy of every chromosome.
Meiosis: Eukaryotic cell division producing gametes (sex cells).
□ Human gametes are haploid (n) since they have 1 copy of every chromosome.
Which of the following statements about cell division is correct?
a) It is the process by which one parent cell divides into 2 daughter cells.
b) It is an unnecessary process once an organism reaches maturity.
c) It is the process by which two sex cells fuse.
d) It occurs in 2 stages of mitosis then meiosis in all types of cells.
a) It is the process by which one parent cell divides into 2 daughter cells.
Which one of the following best defines binary fission?
a) The process by which one cell splits into two cells.
b) The process by which one cell splits into four cells.
c) The process by which two cells combine to create a new cell.
d) The process by which gametes are created.
a) The process by which one cell splits into two cells.
Binary fission is a type of asexual reproduction commonly used by prokaryotic cells (like bacteria) where one parent cell divides into two identical daughter cells.
Genome: the complete set of _______ of the cell’s DNA.
□ Genetic Material: molecules that determine the inherited traits of an organism (usually ( _______).
□ DNA associates with proteins called (______________ to form units called nucleosomes.
□ (c) Nucleosomes: units of ______ histone proteins at the core with DNA wrapped around it.
genetic material
DNA
histones
8
Nucleosomes in a cell take different forms depending on if the cell is ______-dividing or _______________.
□ Chromatin: _________________ packed/coiled nucleosomes in non-dividing cells.
d
□ Chromosomes: ______________ packed, highly condensed, nucleosomes in a dividing cell.
non
dividing
Loosly
Tightly
A collection of DNA and associated proteins in a cell defines the term:
Chromatin.
Choose the option that correctly lists the following genetic material in a dividing cell from smallest to largest.
a) DNA, Chromatin, Nucleosomes, Chromosomes.
b) Chromatin, Nucleosomes, Chromosomes, DNA.
c) DNA, Nucleosomes, Chromatin, Chromosomes.
d) Chromosomes, Chromatin, Nucleosomes, DNA.
c) DNA, Nucleosomes, Chromatin, Chromosomes.
_____ is the smallest unit (single molecule).
_____ are DNA wrapped around histone proteins.
_____ consists of multiple nucleosomes loosely packed.
______ are the most condensed form of DNA, visible during cell division.
DNA is the smallest unit (single molecule).
Nucleosomes are DNA wrapped around histone proteins.
Chromatin consists of multiple nucleosomes loosely packed.
Chromosomes are the most condensed form of DNA, visible during cell division.
Before a cell can divide, the DNA must be replicated (synthesized/duplicated).
□ DNA Replication: produces an exact __________ of all the DNA in a cell.
□ Converts ______replicated chromosomes –> replicated chromosomes with ____ identical “sister” chromatids.
□ Chromatid: ______ of a replicated chromosome joined to another chromatid at the ___________________.
□ DNA Replication: produces an exact copy of all the DNA in a cell.
□ Converts unreplicated chromosomes –> replicated chromosomes with two identical “sister” chromatids.
□ Chromatid: one half of a replicated chromosome joined to another chromatid at the centromere.
Chromatid: One of a replicated chromosome joined to another chromatid at the ______.
Chromatid: One of a replicated chromosome joined to another chromatid at the centromere.
“Sister chromatids” are:
a) Genetically identical & attached by a centromere.
b) Genetically different & attached by a centromere.
c) Genetically different & attached at the genome.
d) Genetically identical & attached at the chromosome.
a) Genetically identical & attached by a centromere.
●Cell ____________: a representation of the events that a cell performs from the moment it is formed to when it divides.
□ Cell cycle is broken down into _____ major phases:
1) _________________: a non-dividing phase for cell growth, DNA replication & production of organelles/enzymes.
□ Includes 4 subphases: ______, ______, ______ & ______.
2) _____ (Mitotic) Phase: a dividing phase that separates the genetic material while producing multiple cells.
□ M Phase = _____________ + Cytokinesis.
□ Mitosis consists of ______ phases
cycle
2
Interphase
G0, G1, S, and G2.
M
M Phase = Mitosis + Cytokinesis
Mitosis consists of 4 phases:
Prophase Metaphase Anaphase Telophase
When cells exit either semi-permanently or permanently from the cell cycle and develop a specific function, they are said to be in _____ phase.
a) G0. b) G1. c) G2. d) G3. e)S.
a) G0.
Explanation:
The G0 phase is a resting or non-dividing state where cells exit the cell cycle. Cells in G0 are often specialized (differentiated) and perform specific functions, like nerve or muscle cells. Some cells remain in G0 permanently, while others can re-enter the cell cycle if needed for repair or regeneration.
______ is a non-dividing stage of cell growth and organelle/enzyme production in preparation for cell division.
It makes up the majority of the cell cycle (Interphase takes a long time), while the ___phase is relatively short.
Interphase, M-phase
Interphase is a non-dividing stage of cell growth and organelle/enzyme production in preparation for cell division.
3 sub-phases:
G1 (Growth): The cell performs its normal functions, growing and producing organelles, enzymes, and proteins.
S (Synthesis): DNA synthesis/replication occurs, producing replicated chromosomes with 2 sister chromatids.
A cytoplasmic protein called the centrosome is also replicated in the S phase.
G2 (Growth): The cell continues growth and produces new proteins required for the M phase (Mitosis).
Additional Phase
G0 Sub-phase: A non-dividing phase where cells do not replicate their DNA nor prepare for division.
Cells may enter G0 temporarily or permanently depending on their function (e.g., nerve cells).
Cells spend the majority of their time in which one of the following phases of the cell cycle?
a) Interphase. b) Prometaphase. c) Metaphase. d) Anaphase.
a) interphase
Interphase is a non-dividing stage of cell growth and organelle/enzyme production in preparation for cell division.
3 sub-phases:
__ (Growth): The cell performs its normal functions, growing and producing organelles, enzymes, and proteins.
__(Synthesis): DNA ________occurs, producing replicated chromosomes with 2 sister chromatids.
—–>A cytoplasmic protein called the _____ is also replicated in this phase.
__ (Growth): The cell continues growth and produces new proteins required for the___phase (_____).
*Additional Phase
G0 Sub-phase: A non-dividing phase where cells do not replicate their DNA nor prepare for division.
Cells may enter G0 temporarily or permanently depending on their function (e.g., nerve cells).
G1 (Growth): The cell performs its normal functions, growing and producing organelles, enzymes, and proteins.
S (Synthesis): DNA synthesis/replication occurs, producing replicated chromosomes with 2 sister chromatids.
A cytoplasmic protein called the centrosome is also replicated in the S phase.
G2 (Growth): The cell continues growth and produces new proteins required for the M phase (Mitosis).
Additional Phase
G0 Sub-phase: A non-dividing phase where cells do not replicate their DNA nor prepare for division.
Cells may enter G0 temporarily or permanently depending on their function (e.g., nerve cells).
The first phase in the cell cycle (G1) corresponds to ___________.
a) The phase between DNA replication and the M phase.
c) The phase in which DNA is being replicated.
b) The beginning of mitosis.
d) Normal growth and cell function.
d) Normal growth and cell function.
Explanation:
G1 phase (Growth 1) is the first phase in the cell cycle, where the cell undergoes normal growth and performs its usual functions. The cell also produces organelles, enzymes, and proteins necessary for the next stages of the cycle. It's not the phase in which DNA is replicated (that's the S phase) or where mitosis begins (that's M phase).
_____ is the ability to do work or cause change. Examples: kinetic, potential, chemical, light, thermal.
Energy is the ability to do work or cause change. Examples: kinetic, potential, chemical, light, thermal.
Cells require _____ for essential processes like growth, movement, transport, and synthesis. Without a consistent supply, these processes cease, leading to cellular death.
Cells require energy for essential processes like growth, movement, transport, and synthesis. Without a consistent supply, these processes cease, leading to cellular death.
_____ Energy: Phototrophic organisms (plants, algae) convert light into chemical energy (sugars) via photosynthesis.
Light Energy: Phototrophic organisms (plants, algae) convert light into chemical energy (sugars) via photosynthesis.
_____ Energy: Heterotrophic organisms (animals, fungi) obtain energy by consuming organic molecules (food).
Chemical Energy: Heterotrophic organisms (animals, fungi) obtain energy by consuming organic molecules (food).
___ is the cell’s primary energy currency. Its _____ bonds store readily available energy that can be released when hydrolyzed, powering cellular work.
ATP is the cell’s primary energy currency. Its phosphate bonds store readily available energy that can be released when hydrolyzed, powering cellular work.
_______ _______ are series of enzyme-catalyzed reactions that break down or build up molecules. They gradually release or capture energy, converting it into ATP through processes like cellular respiration or photosynthesis.
Metabolic pathways are series of enzyme-catalyzed reactions that break down or build up molecules. They gradually release or capture energy, converting it into ATP through processes like cellular respiration or photosynthesis.
_____ reactions involve electron transfer.
*_____ ______: molecule that loses electrons (oxidized).
*_____ _____: molecule that gains electrons (reduced).
*______: loss of electrons.
*_____: gain of electrons.
Redox reactions involve electron transfer.
Electron donor: molecule that loses electrons (oxidized). Electron acceptor: molecule that gains electrons (reduced). Oxidation: loss of electrons. Reduction: gain of electrons.
