During which stage of the cell cycle is DNA copied before cell division occurs?
S Phase of Interphase
In S (synthesis) phase, DNA replication occurs before mitosis so each daughter cell receives identical genetic information.
What process produces two genetically identical daughter cells from a single eukaryotic cell?
Mitosis
Mitosis maintains chromosome number and produces cells genetically identical to the parent cell.
Why do many specialised cells in multicellular organisms no longer divide?
Differentiation
Highly specialised cells often lose the ability to undergo the cell cycle once fully differentiated.
True or False:
DNA replication occurs during mitosis.
False
DNA replication occurs in interphase, before mitosis begins.
In which stage of mitosis do chromosomes condense and become visible under a microscope?
Prophase
Chromatin coils into visible chromosomes and the nuclear envelope begins to break down.
At which stage of mitosis do chromosomes align along the cell equator?
Metaphase
Chromosomes attach to spindle fibres and line up at the equator/metaphase plate.
During which stage of mitosis are sister chromatids pulled apart to opposite poles of the cell?
Anaphase
Spindle fibres shorten and separate chromatids at the centromere.
In which stage of mitosis do nuclear membranes reform around separated chromosomes?
Telophase
Chromosomes decondense and two nuclei begin to form.
What structures attach to centromeres and pull chromatids apart during mitosis?
Spindle fibres
Spindle fibres are microtubules that move chromosomes during cell division.
Fill in the blank:
The division of the cytoplasm that usually follows mitosis is called ______.
Cytokinesis
Cytokinesis physically separates the two daughter cells.
True or False:
After mitosis, the daughter cells contain identical copies of the parent cell’s DNA.
True
Each daughter cell receives the DNA that was replicated during interphase.
What uncontrolled biological process can lead to the formation of tumours?
Uncontrolled cell division
Loss of regulation of the cell cycle can result in tumour formation and cancer.
Many cancer treatments aim to disrupt which biological process?
Cell division
Treatments often target rapidly dividing cells to slow tumour growth.
What type of cell division occurs in prokaryotic cells to produce two daughter cells?
Binary fission
Binary fission is simpler than mitosis and occurs in bacteria and other prokaryotes.
In prokaryotes, what type of DNA molecule is replicated before the cell divides?
Circular DNA
Prokaryotes typically possess a single circular chromosome.
Small extra DNA molecules that may also replicate during prokaryotic cell division are called what?
Plasmids
Plasmids can be present in variable numbers and may carry useful genes such as antibiotic resistance.
True or False:
Viruses divide by mitosis inside host cells.
False
Viruses are non-living and rely on host cell machinery to replicate their genetic material.
When studying mitosis in plant root tips, what type of microscope is typically used in school laboratories?
Optical microscope
Stained root tip squashes allow stages of mitosis to be observed.
Fill in the blank:
The formula used to determine real cell size is: actual size = image size ÷ ______.
Magnification
Magnification must be known to convert measured image size to real size.
What value is calculated by dividing the number of cells in mitosis by the total number of cells observed?
Mitotic index
The mitotic index estimates how actively cells in a tissue are dividing.
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3.1.1 Monomers & Polymers9
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3.1.2 Carbohydrates22
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3.1.3 Lipids17
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3.1.4 Proteins39
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3.1.5 Nucleic Acids32
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3.1.6 ATP11
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3.1.7 Water11
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3.1.8 Inorganic ions8
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3.2.1 Cell structure52
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3.2.2 Cell division20
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3.2.3 Transport across cell membranes20
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3.2.4 Cell recognition & the immune system36
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3.3.1 Surface area to volume ratio13
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3.3.2 Gas exchange24
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3.3.3 Digestion & absorption16
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3.3.4 Mass transport39
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3.4.1 DNA, genes & chromosomes13
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3.4.2 DNA & protein synthesis14
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3.4.3 Genetic diversity & meiosis14
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3.4.4 Genetic diversity & adaptation20
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3.4.5 Species & taxonomy20
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3.4.6 Biodiversity within a community12
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3.4.7 Investigating diversity12
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3.5.1 Photosynthesis23
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3.5.2 Respiration17
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3.5.3 Energy & ecosystems20
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3.5.4 Nutrient cycles15
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3.6.1 Stimuli & Response62
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3.6.2 Nervous coordination53
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3.6.3 Skeletal muscles14
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3.6.4 Homeostasis57
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3.7.1 Inheritance12
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3.7.2 Populations15
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3.7.3 Evolution may lead to speciation22
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3.7.4 Populations in ecosystems24
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3.8.1 Gene Mutations and Protein Structure14
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3.8.2 Control of Gene Expression44
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3.8.3 Applications of Genome Projects10
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3.8.4 Gene Technologies and Their Applications46
