Biology: Cells And Control Flashcards
What does a nucleus contain?
Your genetic material in the form of chromosomes
What are chromosomes?
Coiled up lengths of DNA molecules
What do body cells usually have in terms of chromosomes? What does this make the cell? Where do these come from?
Body cell has two copies of each chromosome, magic the cell a diploid cell. One chromosome comes from organisms ‘mother’, one from ‘father’
What is the result of miosis?
Two cells identical to the original cell. Nucleus of each new cell contains same number of chromosomes as original cell.
What does the cell cycle produce?
New cells, to replace damaged cells and to grow as an organism
What is the cell cycle?
The process in which body cells in multicellular organisms divide to produce new cells during a process called the cell cycle.
What is the stage of the cell cycle when the cell divides called?
Mitosis
What is mitosis in the cell cycle?
The stage where the cell divides
What is it called when organisms use mitosis to produce?
Asexual reproduction
What are the three purposes of mitosis?
Growth, repair, asexual reproduction
What are the main phases of the cell cycle?
Interphase, mitosis and cytokinesis
What happens in interphase?
DNA is spread out in long strings. Cell grows to increase amour to of subcellular structures such as mitochondria and ribosomes. Then duplicates DNA.
Give the four steps of mitosis
Prophase
Metaphase
Anaphase
Telophase
What happens in prophase?
Chromosomes condense, membrane around nucleus breaks down, so chromosomes lie free in the cytoplasm
What happens in metaphase?
Chromosomes line up at centre of cell
What happens in anaphase?
Cell fibres pull chromosomes apart. Two arms of each chromosome go to opposite ends of the cell
What happens in telophase?
Membranes form around each of the sets of chromosomes. These become nuclei of the two new cells.
What happens in cytokinesis?
Cytoplasm and cell membrane divide to form two separate cells
When does cytokinesis take place?
Before telophase ends
What is the formula to calculate the number of cells there’ll be after multiple divisions of cells by mitosis?
Number of cells = 2^n
N= number of divisions by mitosis
You start with 1 cell. After 5 divisions of mitosis, how many cells will there be?
2^5 = 2x2x2x2x2 = 32 cells
What is growth?
An increase in size of mass
What is cell differentiation?
The process by which cell changes to become specialised for its job, allowing multicellular organisms to work more efficiently
What is cell elongation?
Where the cell expands, making the cell bigger and so making the plant grow