Cell Division And Cellular Organisation

Question 1

What is the cell cycle?

Answer 1

The process all multicellular organisms use to grow and divide

Question 2

What happens in G1 (Gap phase 1) of the cell cycle?

Answer 2

The cell grows and proteins are made

Question 3

What happens at G1 checkpoint?

Answer 3

The cell checks all the chemicals needed for replication are present

Question 4

What happens in S (synthesis) stage of the cell cycle?

Answer 4

The cell replicates its DNA

Question 5

What happens in G2 (Gap phase 2) of the cell cycle?

Answer 5

Cell keeps growing and proteins needed for cell division are made

Question 6

What happens at G2 checkpoint?

Answer 6

Cell checks whether DNA has been replicated without damage

Question 7

What happens in the M phase of the cell cycle?

Answer 7

Mitosis (IPMAT) and Cytokenesis

Question 8

What happens in interphase?

Answer 8

The cell grows and replicated DNA ready for division

Question 9

What happens in prophase?

Answer 9

The chromosomes condense, and bundles of protein called centrioles move to the end of the cell and spindle fibres are formed. The nuclear envelope also breaks down here.

Question 10

What happens in metaphase?

Answer 10

Chromosomes line up along the middle of the cell and spindle fibres attach to the centromere.

Question 11

What happens in anaphase?

Answer 11

Centromeres divide and separate each pair of sister chromatids, pulling them to opposite ends of the cell.

Question 12

What happens in telpohase?

Answer 12

Chromatids uncoil and become long and thin, making them chromosomes. The nuclear envelopes forms again.

Question 13

What happens in cytokinesis?

Answer 13

The cytoplasm divides and a cleavage furrow forms to divide the membrane.

Question 14

What is left (the product) after cytokinesis?

Answer 14

Two genetically identical daughter cells

Question 15

How can you visualise the stages of mitosis?

Answer 15

Stain the chromosomes and place them under a microscope

Question 16

What does meiosis produce?

Answer 16

Gametes for sexual reproduction

Question 17

What happens in meiosis 1?

Answer 17

PMATC just like in mitosis

Question 18

What happens in meiosis 2?

Answer 18

The two daughter cells undergo P2 M2 A2 T2 and C (PMAT and C) only the new daughter cells only have one chromatid from each chromosome.

Question 19

What phase does crossing over occur in in meiosis?

Answer 19

Prophase 1

Question 20

What happens in crossing over?

Answer 20

Chromatids twist around one another and some chromatids swap over, meaning the chromatids contain the same genes but a different combination of alleles

Question 21

What two events lead to genetic variation in meiosis?

Answer 21

Crossing over and independent assortment of chromosomes

Question 22

What is the independent assortment of chromosomes?

Answer 22

When homologous pairs line up in M1 and separated in A1, it’s completely random so the four daughter cells have different combinations of maternal and paternal genes

Question 23

What type of cells are stem cells?

Answer 23

Unspecialised cells

Question 24

What are unspecialised cells?

Answer 24

They can develop into different types of cells

Question 25

Where are stem cells found in humans?

Answer 25

Early embryos and bone marrow

Question 26

What do stem cells in bone marrow differentiate into?

Answer 26

Blood cells (erythrocytes - RBC’s) (neutrophils - WBC’s) to replace worn out blood cells

Question 27

What do stem cells in the meristem differentiate into?

Answer 27

Xylem vessels and phloem sieve tube elements.

Question 28

How could stem cells cure Alzheimer’s?

Answer 28

By regrowing healthy nerve cells

Question 29

How could stem cells cure Parkinson’s?

Answer 29

To regenerate dopamine producing cells.

Question 30

How are neutrophils adapted to their function?

Answer 30

Their flexible shape allows them to engulf pathogens and the lysosomes in their cytoplasm allies them to digest.

Question 31

How are erythrocytes adapted to their function?

Answer 31

Their biconcave disc shape provides a large SA for gas exchange and they have no nucleus so there’s more room for haemoglobin.

Question 32

How are epithelial cells adapted to their functions?

Answer 32

Some are ciliated to move particles away and some are squamous that are thin so there is a short diffusion distance.

Question 33

How are sperm cells adapted to their function?

Answer 33

Have a flagellum so they can swim to the egg and their acrosome contains digestive enzymes to enable the sperm to penetrate the egg

Question 34

How are palisade mesophyll cells adapted to their function?

Answer 34

They contain many chloroplasts so they can absorb sunlight and the walls are thin so co2 can easily diffuse into the cell

Question 35

How are root hair cells adapted to their function?

Answer 35

They have a large surface area for reabsorption and a thin permeable cell wall for entry

Question 36

How are guard cells adapted to their function?

Answer 36

Thin outer walls and thick inner walls that forces them to bend outwards to open the stomata

Question 37

What are the three different types of muscle tissue and where are they found?

Answer 37

Smooth - Stomach wall Cardiac - Heart Skeletal - Used to move

Question 38

What is cartilage and where is it found?

Answer 38

A connective tissue in the joints

Question 39

Name the 4 animal tissues

Answer 39

1) Squamous epithelium 2) Ciliated epithelium 3) Muscle tissue 4) Cartilage

Question 40

Name the two plant tissues

Answer 40

Xylem and phloem

Question 41

What does xylem tissue do?

Answer 41

Transports water

Question 42

What is xylem made up of?

Answer 42

Dead and living parenchyma cells

Question 43

What does phloem tissue do?

Answer 43

Transports sugars

Question 44

What is phloem tissue made up of?

Answer 44

Sieve tube elements, companion cells and sieve plates in between the tube

Question 45

What is an organ?

Answer 45

A group of tissues that work together to perform a particular function

Question 46

What tissues do the lungs have?

Answer 46

Squamous and ciliated epithelial, elastic connective tissue and vascular tissue

Question 47

What tissues to leaves have?

Answer 47

Palisade tissue, epidermal tissue, xylem and phloem

Question 48

What do organs work together to form?

Answer 48

Organ systems

Question 49

What are the two organ systems?

Answer 49

The respiratory system and the circulatory system