UNIT 2: (2.1) Producing New Cells

Question 1

what is a chromosome complement?

Answer 1

the definite number of chromosomes in each species of plants and animals

Question 2

how many chromosomes are in most humans cells?

Answer 2

46

Question 3

how many pairs of chromosomes are in most human cells?

Answer 3

2

Question 4

what is meant by diploid?

Answer 4

any cell that contains two sets of matching chromosomes (2n)

Question 5

what cells only contain one set of chromosomes?

Answer 5

gametes (sex cells)

Question 6

what is meant by haploid?

Answer 6

any cell that contains only one set of chromosomes (n)

Question 7

how many chromosomes are in gametes?

Answer 7

23

Question 8

what are examples of haploid animal cells?

Answer 8

• sperm cell

- egg cell

Question 9

what are examples of haploid plant cells?

Answer 9

• pollen grain

- ovule

Question 10

what are examples of diploid animal cells?

Answer 10

• cheek cell
• nerve cell
• heart cell

Question 11

what are examples of diploid plant cells?

Answer 11

• root hair cell

Question 12

what is the importance of mitosis?

Answer 12

• mitosis provides new cells for growth and repair of damaged cells
• mitosis maintains the diploid chromosome complement
• in single-celled organisms, mitosis provides a means of reproduction

Question 13

what is mitosis?

Answer 13

-takes place in diploid cells.
-when the nucleus divides into 2 daughter nuclei each of which receives exactly the same number of chromosomes that were present in the original nucleus.
maintains the full chromosome complement.

Question 14

what is stage one in the process of mitosis?

Answer 14

chromosomes shorten, thicken and become visible as each chromosome makes a duplicate copy of itself ( chromosomes are now made up of pairs of chromatids)
Nuclear membrane begins to disintegrate and spindle fibres appear

Question 15

what is stage 2 in the process of mitosis?

Answer 15

chromosomes now line up at the equator of the cell attached to the spindle fibres

Question 16

what is stage 3 in the process of mitosis?

Answer 16

the spindle fibres contract, separating the pairs of chromatids
chromosomes now move to opposite ends ( poles) of the cell

Question 17

what is stage 4 in the process of mitosis?

Answer 17

a nuclear membrane forms around each group of chromosomes and the cytoplasm divides
two new daughter cells are formed with a chromosome complement identical to the parent cell

Question 18

how many chromosomes do cells contain at the start and end of mitosis?

Answer 18

4

Question 19

were do all cells in the body originate from?

Answer 19

stem cells

Question 20

what are stem cells?

Answer 20

unspecialized cells which can divide in order to self-renew. they have the potential to become different types of cell

Question 21

what are stem cells involved in?

Answer 21

growth and repair

Question 22

what sources do stem cells come from?

Answer 22

• embryos (embryonic stem cells)

- certain adult tissues (tissue stem cells)

Question 23

were do embryotic stem cells come from?

Answer 23

• 4 or 5 day old human embryos

Question 24

where do tissue stem cells come from?

Answer 24

• brain
• bone marrow
• blood
• blood vessels
• skeletal muscles
• skin
• liver

Question 25

what is the function of the sperm cell?

Answer 25

to fertilize the egg

Question 26

what are the specialised structures of a sperm cell?

Answer 26

- tail for movement to swim to the egg | - many mitochondria to provide energy to swim

Question 27

what is the function of the red blood cells?

Answer 27

specialized to transport oxygen efficiently in the form of oxyhemoglobin

Question 28

what are the specialized structures of red blood cells?

Answer 28

- biconcave in shape to increase the surface area to allow more oxygen to be absorbed - haemoglobin which binds to oxygen - no nucleus so more space for haemoglobin

Question 29

what is the function of the neuron?

Answer 29

specialized to carry messages as electrical impulses around the body

Question 30

what are the speacialed structures of a neuron?

Answer 30

- many connections at the end allowing one nerve cell to reach other nerve cells - very long to carry information from one part of the body to another

Question 31

what are examples of specialized animal cells?

Answer 31

- sperm cell - red blood cells - neurons

Question 32

what are examples of specialised plant cells?

Answer 32

- root hair cell | - palisade cell

Question 33

what is the function of a root hair cell?

Answer 33

specialised for absorbing water and dissolved minerals

Question 34

what are the specialised structures of a root hair cell?

Answer 34

- long root hair attached to the root cell increases the surface area helps absorption of water and minerals - thin cell wall easier for minerals to pass across

Question 35

what is the function of the palisade cell?

Answer 35

specialised for photosynthesis

Question 36

what are the specialised structures of palisade cell?

Answer 36

- lots of chloroplasts which have chlorophyll which absorbs light energy - near-surface, column-shaped and closely packed together for continuous layer for absorption of sunlight

Question 37

what does specialisation of cells lead to?

Answer 37

variety of cells, tissues and organs

Question 38

what is the hierarchy of organisation?

Answer 38

cells ----> tissues -----> organs -----> systems

Question 39

what is a tissue?

Answer 39

a group of specialised cells that have a similar structure and function

Question 40

what is an organ?

Answer 40

groups of different tissues working together to perform a particular function

Question 41

what is a system?

Answer 41

a group of organs which work together to perform a particular function

Question 42

what is an example of a system?

Answer 42

circulatory system were the heart and blood vessels work together to transport substances around the body

Question 43

what do multicellular have?

Answer 43

more than one cell type and are made up of tissues and organs