Cell division And Diversity

Question 1

what is cell continuity

Answer 1

every cell develops from existing cells.

Question 2

what is a chromosome

Answer 2

a structure which consists of protein and DNA that carries genetic information in the form of genes

Question 3

what is chromatin

Answer 3

condensed chromosomes that are seen in the cell when not dividing

Question 4

what is a gamete

Answer 4

a sex cell

Question 5

what is a gene

Answer 5

a short section of DNA that codes for a protein

Question 6

what is junk DNA

Answer 6

DNA that doesnt code for a protein

Question 7

what is the genome

Answer 7

all the genes in the organism

Question 8

what is the locus

Answer 8

the position of a gene on a chromosome

Question 9

how many chromosomes in a human cell

Answer 9

46, 23 pairs

Question 10

what are a homologous pair of chromosomes

Answer 10

a pair of chromosomes which have the same types of genes at the same loci, one from the mother, one from the father

Question 11

what are sister chromatids

Answer 11

chromosomes that are identical to each other stuck together by a centromere, they are produced in late interphase by DNA replication

Question 12

what is interphase

Answer 12

the non dividing phase of the cell, the cell is in this phase for 90% of its cycle

Question 13

what occurs during early interphase

Answer 13

normal cell functions and replication of cell organelles

Question 14

what occurs in late interphase

Answer 14

DNA is replicate on each chromosome producing an identical copy of each chromosome, the copied chromosome is stuck to the original by the centromere which holds the two identical chromosome together

Question 15

what happens during prophase

Answer 15

the nuclear membrane disintegrates, chromosomes become visible from chromatin, spindle fibres appear in cytoplasm

Question 16

what occurs in metaphase

Answer 16

the spindle fibres move to the poles of the cell, chromosomes align along the equator of the cell, spindle fibres become fully formed and attach to the centromeres

Question 17

what occurs in anaphase

Answer 17

spindle fibres contract, splitting the centromere and pulling apart the identical chromosomes, chromosomes pulled back to the poles of the cell

Question 18

what occurs during telophase

Answer 18

nuclear membrane forms around chromosomes at each pole, spindle fibres disappear, chromosomes begin to become chromatin again

Question 19

what occurs for animal cell during cytokinesis

Answer 19

groove forms in cytoplasm called cleavage furrow which deepens until it splits into 2 identical cells

Question 20

what happens to plant cells during cytokinesis

Answer 20

cell plate forms from the vesicles in plant cells, a middle lamella forms in the cell plate to divide the two identical cells

Question 21

what is the function of mitosis

Answer 21

unicellular is used for reproduction eg binary fission and multicellular is used for growth and repair

Question 22

what is cancer

Answer 22

a group of disorders in which cells lose control over the rate and number if divisions they undergo, this results in the uncontrolled multiplication of cells

Question 23

what are the causes of cancer

Answer 23

carcinogens and oncogenes

Question 24

what is the treatment for cancer

Answer 24

chemotherapy, radiation and surgery

Question 25

what is meiosis

Answer 25

nuclear division in which one nucleus divides to form four nuclei with half the number of chromosomes

Question 26

what is the function of meiosis

Answer 26

to produce gametes or haploid cells in sexual reproduction so the parental chromosome is the same after sexual reproduction and to introduce variation in species.

Question 27

What is an organ?

Answer 27

A group of tissues with the same functions working together.

E.g. Plant: Leaf, stem or e.g. Animal: Heart, Liver

Question 28

What is a system?

Answer 28

A group of organs with similar functions that work together. (Digestive System)

Question 29

What are plant tissues?

Answer 29

Xylem and dermal.

Question 30

What is Xylem?

Answer 30

Xylem found in the vascular tissue of a Stem and veins in leaves. Dead cells, contents hollow. Cell wall contains lignin. Transports water. Has Continuous side pits to allow water to pass from cells which are side by side.

Question 31

What is Dermal Tissue?

Answer 31

Outside layer of tissue in plant (epidermis). Function is primarily protection. Cell wall is thick sometimes has a waterproof layer called a Cuticle in leaves and stoma

Question 32

What are animal tissues?

Answer 32

Connective tissue and nervous tissue

Question 33

What is Connective Tissue?

Answer 33

Found in many areas (Bone, Blood, Cartilage). Many functions -R.B.C’S function is to carry oxygen around the body. Many types -R.B.C is concave in shape, has no nucleus or mitochondria.

Question 34

What is Nervous Tissue?

Answer 34

the tissue that makes up the brain, spinal cord, and nerves. It is responsible for transmitting electrical impulses and enabling communication between different parts of the body.

Question 35

What are the uses of Tissue Culturing?

Answer 35

1. Micropropagation
2. Cancer Research
3. Skin Grafts

Question 36

What is Tissue Culturing?

Answer 36

Tissue Culturing is a method where cells are grown in a sterile nutrient medium outside an organism. Usually Involves: Nutrients, Oxygen, Sterile Conditions, Growth Substances. Optimum Growth Conditions such as temperature and pH.

Question 37

What is Micropropagation?

Answer 37

Micropropagation is the use of tissue culturing to produce many genetically identical organisms.

Question 38

Benefits of micropropagation:

Answer 38

all organisms are genetically identical and produces large numbers of plants very quickly.

Question 39

Disadvantages of micropropagation:

Answer 39

susceptible to disease due to lack of variation as they are genetically identical and its expensive.