cell division Flashcards
interphase
-first stage
-inital growth phase
-extra ribosomes, mitochondria and other sub-cellular structures are produced
-the cell’s chromosomes are replicated so there are two sets of cell chromosomes
mitosis
-the two sets of chromosomes are pulled to opposite ends of the cell
-then the nucleus divides into two
cytokinesis
-the cytoplasm and cell membrane divides to make two identical diploids cells
what happens during mitosis?
-prophase-chromosomes condense
metaphase-chromosomes line up along the middle of the cell
anaphase-the two sets of chromosomes are pulled to opposite ends of the cell
telophase-the nucleus splits and two nuclei are formed
identical daughter cells-mitosis ensures that both daughter cells have the same chromosomes as each other and also the parent cell
-this is important for processes that require identical cells to be produced such as the growth and repair of tissues and asexual reproduction
malignant tumour
malignant tumours can invade neighbouring tissues and spread throughout the body in the blood, leading to the creation of more secondary tumours
benign tumours
-benign tumours stay in a specific part of the body, often within the membrane
explain zone of cell division
-this zone is near the tip of the root
-cells divide by mitosis and new cells are created
explain zone of elongation
-this zone is further up the root, next to the zone of cell division
-here, the cell grows in size
explain the zone of differentiation
-this zone is even further up the root next to the zone of elongation
-this is where the new cells differentiate(specialise into different types of cells)
what are percentile charts?
-whenever a baby is born, their growth is compared to that of millions of other babies to make sure that they are growing as they should be, this is represent by percentile charts
-if a baby is in the 1st percentile, this means that 99 percent of other babies that age are heavier, this could mean that it is developing too slowly and doctors can then investigate this
what happens in cell differentiation?
-cell differentiation is the process where a cell develops new sub-cellular structures to let it perform a specific function
-when this happens the cell becomes specialised
embryos (in cell differentiation)
-cell differentiation happens during an organisms development
-organisms start at one cell
-these cells divide to form embryos that differentiate to produce cells that can perform all of the body’s functions
plants (cell differentiation)
-many plants keep their ability to differentiate throughout their life
-because of this, plants are always able to create new tissues
adult animals (cell differentiation)
-cell differentiation is rare in mature animals
-their cells mostly divide in order to replace cells and repair tissues
-new tissues are rarely created
what are stem cells?
-stem cells are undifferentiated cells that have not yet specialised to perform a specific function
-they cane create more stem cells or differentiate to perform another function
stem cells found in embryos
-the stem cells in embryos can differentiate into most cell types to produce all cell types that will make up the organism
stem cells found in plant meristems
-plant stems cells are found in the meristem tissue
-plant stem cells can differentiate into all types of plant cells throughout the life of the plant, this allows plants to grow for their whole lives
stem cells found in bone marrow
-in human adults, stem cells can be found in bone marrow
-adult stem cells differentiate into fewer cell types than stem cells in embryos
-they are used to replace dying cells and damaged tissue
what are different types of treatments used with stem cells?
-stem cells may be used for replacing damaged cells in the body that cause diabetes or paralysis
-they can be used to treat patients with burn injuries, arthritis, and Parkinson’s disease
what is therapeutic cloning?
-theraputic cloning is a process that produces an embryo with the same genes as the patient
-stem cells taken away from this embryo will have the same DNA as the patient, this means that the body will not reject he stem cells or body cells made from the embryo’s stem cells
-this is is ideal for use in stem cell medical treatments
what are the disadvantages of stem cells
-VIRAL INFECTIONS, stem cell transplantation could transfer viral infections
-ETHICAL BELIEFS, they believe that life begins at contraception which means an embryo is alive, they therefore view the embryonic stem cells as ‘killing’ an embryo
-REJECTION, introducing stem cells to a patient’s body could cause the immune system to reject and Destry the new cells
what does exponential increase mean?
Exponential growth is a process that increases quantity over time. It occurs when the instantaneous rate of change of a quantity with respect to time is proportional to the quantity itself.
what does plateaus mean?
to reach a stage with little or no decline
How do you think the reaction rate will be affected if you increase the temperature ?
-rate of respiration would increase as the temperature increases
-bove a certain temp, he rate would start to decrease
-eventually the reaction stops because enzymes denature at high temperatures
Why do you think yeast mass increases rapidly initially and then plateaus (remains the same)?
-initally resources are plentiful so the population of mass is a exponential growth
-however when the resources are used up, it limits the population size so the mass remains the same
If you were to design an experiment investigating the effect that temperature has on rate of anaerobic respiration in yeast, what will you need to measure in order to calculate the reaction rate?
-concentration of alcohol over time
-volume of carbon dioxide produced over time
If you were to design an experiment investigating the effect that temperature has on the rate of anaerobic respiration in yeast, which of the following conditions would you control?
-concentration of sugar solution
-initial mass
Describe how the structure of a red blood cell is related to its function.
-to bind oxygen
-contains haemoglobin
Describe the function of platelets.
clotting / to seal a wound /
scab formed
compare mitosis and meiosis
-mitosis,2 daughter cells, one division, identical sets of chromosomes
-meiosis,2 divisions, haploid daughter cells,half the number of chromosomes
The term used to describe the number of chromosomes in an egg or sperm
cell is
(1)
-haploid
