3.2.2 All Cells Arise From Other Cells Flashcards
3 parts to cell theory
Cells are the basic unit of life
All organisms are made up of 1 or more cells
All cells come from cells
Unicellular vs multicellular organisms
Unicellular organisms are made up of only 1 cell
Multicellular organisms are made up of more than 1 cell (many cells)
Organisms made up of only 1 cell are described as being…
Unicellular
Organisms made up of many cells (more than 1 cell) are described as being..,
Multicellular
2 stages of binary fission of prokaryotic cells e.g bacteria
Circular DNA and plasmids are replicated
The cytoplasm divides to produce 2 daughter cells
Prokaryotic cells divide by a process called…
Binary fission
Prokaryotic cells divide by a process called…
Binary fission
Which stage of the cell cycle does DNA replication occur in
Interphase
In which stage of the cell cycle is there cell growth
Interphase
True or false, within multicellular organisms, all cells can divide
False
In the interphase if the cell cycle, the cell processes that occur use the acronym DOCTOR- what does it stand for
DNA replication
Organelle duplication e.g mitochondria
Cell growth (cytoplasmic volume must increase before cytoplasm divides)
Transcription/ translation (key proteins and enzymes must be synthesised)
Obtain nutrients (vital cellular materials must be present before division)
Respiration (aerobic) (ATP production is needed to drive the division process)
True or false, the interphase is part of mitosis
False
The interphase is the stage that happens before mitosis (before the cells divide)
Cytokinesis meaning
Division of cytoplasm
(happens as last stage of mitosis/ the stage in the cell cycle after mitosis)
(Sometimes it’s seen as a separate stage to mitosis, sometimes it’s seen as the final stage within mitosis)
Proper term for the division of the cytoplasm
Cytokinesis
What stage is the longest stage in the cell cycle
Interphase (this is the 1st stage)
Which comes first in the cell cycle out of interphase and mitosis
Interphase (it prepares the cell before it starts the process of the actual cell division (mitosis))
True or false, DNA replication occurs during mitosis
False
It occurs before mitosis during the interphase
What are the 4 stages within mitosis
Prophase
Metaphase
Anaphase
Telophase
(PMAT)
What does PMAT stand for
Prophase, metaphase, anaphase, telophase (the correct order of the 4 stages that occur within mitosis)
True or false, the cell cycle just refers to mitosis
False
Mitosis is part of the cell cycle but the cell cycle also includes the interphase (the longest stage of the cell cycle) and cytokinesis
Mitosis is needed for what 2 key things (think back to grr from GCSE but without the last r)
Growth (of multicellular organisms)
Repair (of damaged tissues)
At the beginning of mitosis, each chromosome is made up of 2 strands joined in the middle by a…
Centromere
Before mitosis do chromosomes consist of 1 or 2 strands
2 (joined in the middle by a centromere)
1 individual strand in a chromosome is called a…
Chromatid
A chromatid is…
One individual strand in the chromosome
One strand on a chromosome is called a chromatid. 2 strands on the same chromosome are called…chromatids
Sister
When mitosis is over, do the chromosomes in each daughter cell have 1 or 2 strands (chromatids)
1
Just before mitosis does each chromosome in the cell have 1 or 2 strands (chromatids)
2 (as DNA replication has occurred during the interphase before mitosis)
During the prophase of mitosis when the…condenses, the chromosomes become visible
Chromatin (the strands that make up the chromosome)
Describe and explain the arrangement of genetic material during the prophase of mitosis
The chromosomes are becoming visible because the chromatin is condensing
Describe and explain the arrangement of genetic material during the prophase of mitosis
The chromosomes are becoming visible because the chromatin is condensing
In the prophase of mitosis the chromatin condense which means that the chromosomes get…er and…er
Shorter
Thicker
In the prophase of mitosis what part of the chromosome attaches to the spindle fibre
The centromere (the middle part of the chromosome that joins the 2 chromatids (strands) together)
During the prophase of mitosis the…move to the poles of the cell and form spindle fibres
Centrioles
During the prophase of mitosis the…breaks down
Nuclear envelope (membrane surrounding nucleus)
During the prophase the…disappear
Nucleoli
(And the nuclear envelope disappears but we say that it breaks down)
What happens during the prophase of mitosis
The chromatin condenses so the chromosomes get shorter and thicker and become visible
The nuclear envelope (membrane) breaks down
The nucleoli disappear
Centrioles move to the poles of the cell and form spindle fibres which the centromere of each chromosome attaches to
During the metaphase how many chromatids does each chromosome contain
2
(They’re referred to as sister chromatids)
During the prophase how many chromatids does each chromosome contain
2
(They’re referred to as sister chromatids)
During the metaphase how do the chromosomes arrange themselves
They line up on the equator of the spindle apparatus
(The microtubules of the spindle are attached to the centromere of each chromosome although they were already attached at the end of the prophase)
What do the centromeres do in the anaphase
They divide (so each pair of sister chromatids is separated)
What do the centromeres do in the anaphase
They divide (so each pair of sister chromatids is separated)
In the anaphase the…of each chromosome divides which separates each pair of sister chromatids. The …then shorten and pull the sister chromatids to opposite poles using energy from ATP. (The centromere is the part of the chromatid that is pulled first which makes the chromatids look V shaped)
Centromere
Spindle fibres
In what stage of mitosis do the spindle fibres shorten and why
Anaphase
To be able to pull the sister chromatids to opposite poles
After mitosis are the separated chromatids referred to as chromatids or chromosomes
Chromosomes
In the telophase the…decondense (become longer) and are no longer visible
Chromosomes
(In the prophase you say that the chromatin condenses but in the telophase you say that the chromosomes decondense)
(In both the prophase and telophase you refer to the chromosomes as being visible/ not visible)
In the telophase the chromosomes decondense (become …er)
Longer
What happens to the spindle fibres in the telophase
They break down (as they’re no longer needed after pulling the chromatids to the poles in the anaphase)
In the…phase and…phase of the cell cycle nucleoli and the nuclear membrane are present
Interphase
Telophase
(Check if they are visible under the microscope for both stages and if not what visible means)
What stage of mitosis do the sister chromatids line up at the equator of the spindle apparatus
Metaphase
(Think m for middle as they are lines up in the centre (middle) of the cell)
In what stage of mitosis do the spindle fibres shorten and pull the sister chromatids to opposite poles of the cells
Anaphase
Think An for animal as the chromosomes look v shaped as if they are crab nippers)
In the anaphase what shape do the chromosomes (which were previously referred to as sister chromatids) being pulled to the poles by the spindle fibres look and why
V shaped
The centromere is the part of the chromosome that’s attached to the spindle fibre so it’s the part of the chromosome that’s pulled first
Is mitosis (cell division) a controlled or uncontrolled process
Controlled
In binary fission, each daughter cell produced contains how many copies of the circular DNA
1 (a single copy)
In binary fission each daughter cell produced contains how many copies of the circular DNA
1 (a single copy)
In binary fission each daughter cell produced contains how many copies of plasmids
A variable number
True or false, Eukaryotes, prokaryotes and viruses all undergo cell division
False
Eukaryotes and prokaryotes undergo cell division (eukaryotes by the c all cycle which includes mitosis/ meiosis and prokaryotes by binary fission)
Viruses can’t undergo cell division as they are acellular (have no cells) and are non living so instead replicate inside the host cell
Binary fission produces 2 daughter cells, each with a single copy of…and a variable number of…
The circular DNA
Plasmids
Uncontrolled cell division can lead to the formation of …and…
Tumours
Cancer
Many cancer treatments are directed at controlling the rate of…
Cell division
The 3 domains are… , … and …
Archaea, bacteria, eukarya
Eukarya, bacteria and archaea are all examples of…
Domains
Eukarya, bacteria and archaea are all examples of…
Domains
Compartmentalisation refers to how…surround the organelles to act as a barrier between the organelle and the cytoplasm and to divide the cell into different compartments
Internal membranes
….refers to how internal membranes surround the organelles to act as a barrier between the organelle and the cytoplasm and to divide the cell into different…
Compartmentalisation
Compartments
The cell cycle (including cell division) is needed for what 3 key things
Growth
Replacing damaged tissue
Repair
In the cell cycle, G1, S and G2 are all part of the …
Interphase
(Gap phase 1= cell grows and organelles duplicate, synthesis= DNA replication, Gap phase 2= more cell growth and cell prepares for cell division e.g mitosis)
Why does aerobic respiration need to occur in the interphase
To produce ATP to provide energy for cell division, especially the anaphase
An example of how cancer is treated by targeting the G1 part of the interphase where there is cell growth and protein production
Drugs prevent the synthesis of enzymes need for DNA replication
Without these enzymes, the cell can’t enter the next phase (S phase of the interphase) where DNA replication occurs which disrupts the cell cycle and leads to apoptosis where the cell dies
Example of how cancer is treated by targeting the S phase of the interphase
Radiation/ drugs damage DNA
At several points in the cell cycle, the DNA is checked for damage so if Sever DNA damage is detected then apoptosis will occur where the cell dies
Chemotherapy is a type of cancer treatment that prevents …from happening in the interphase before cell division occurs
DNA replication in the s phase
(It prevents the enzymes being synthesised in the G1 phase that are then needed for DNA replication so DNA replication can’t occur and apoptosis happens (cell death))
…is a type of cancer treatment that inhibits DNA replication by preventing the synthesis of enzymes needed for DNA replication
Chemotherapy
In what stages of mitosis are the chromosomes visible
All of them
(Prophase, metaphase, anaphase, telophase)
Although at the end of telophase, the chromosomes decondense once they’ve reached their poles so are no longer visible