cell division

Question 1

interphase

Answer 1

-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

Question 2

mitosis

Answer 2

-the two sets of chromosomes are pulled to opposite ends of the cell
-then the nucleus divides into two

Question 3

cytokinesis

Answer 3

-the cytoplasm and cell membrane divides to make two identical diploids cells

Question 4

what happens during mitosis?

Answer 4

-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

Question 5

malignant tumour

Answer 5

malignant tumours can invade neighbouring tissues and spread throughout the body in the blood, leading to the creation of more secondary tumours

Question 6

benign tumours

Answer 6

-benign tumours stay in a specific part of the body, often within the membrane

Question 7

explain zone of cell division

Answer 7

-this zone is near the tip of the root
-cells divide by mitosis and new cells are created

Question 8

explain zone of elongation

Answer 8

-this zone is further up the root, next to the zone of cell division
-here, the cell grows in size

Question 9

explain the zone of differentiation

Answer 9

-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)

Question 10

what are percentile charts?

Answer 10

-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

Question 11

what happens in cell differentiation?

Answer 11

-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

Question 12

embryos (in cell differentiation)

Answer 12

-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

Question 13

plants (cell differentiation)

Answer 13

-many plants keep their ability to differentiate throughout their life
-because of this, plants are always able to create new tissues

Question 14

adult animals (cell differentiation)

Answer 14

-cell differentiation is rare in mature animals
-their cells mostly divide in order to replace cells and repair tissues
-new tissues are rarely created

Question 15

what are stem cells?

Answer 15

-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

Question 16

stem cells found in embryos

Answer 16

-the stem cells in embryos can differentiate into most cell types to produce all cell types that will make up the organism

Question 17

stem cells found in plant meristems

Answer 17

-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

Question 18

stem cells found in bone marrow

Answer 18

-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

Question 19

what are different types of treatments used with stem cells?

Answer 19

-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

Question 20

what is therapeutic cloning?

Answer 20

-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

Question 21

what are the disadvantages of stem cells

Answer 21

-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

Question 22

what does exponential increase mean?

Answer 22

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.

Question 23

what does plateaus mean?

Answer 23

to reach a stage with little or no decline

Question 24

How do you think the reaction rate will be affected if you increase the temperature ?

Answer 24

-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

Question 25

Why do you think yeast mass increases rapidly initially and then plateaus (remains the same)?

Answer 25

-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

Question 26

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?

Answer 26

-concentration of alcohol over time
-volume of carbon dioxide produced over time

Question 27

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?

Answer 27

-concentration of sugar solution
-initial mass

Question 28

Describe how the structure of a red blood cell is related to its function.

Answer 28

-to bind oxygen
-contains haemoglobin

Question 29

Describe the function of platelets.

Answer 29

clotting / to seal a wound /
scab formed

Question 30

compare mitosis and meiosis

Answer 30

-mitosis,2 daughter cells, one division, identical sets of chromosomes
-meiosis,2 divisions, haploid daughter cells,half the number of chromosomes

Question 31

The term used to describe the number of chromosomes in an egg or sperm
cell is

(1)

Answer 31

-haploid