Part 3 - Growth

Question 1

Define the term ‘hormone’

Answer 1

A signalling molecule within a multicellular organism; effectively hormones deliver messages between cells

Question 2

Define the term arthropod?

Answer 2

A phylum of the animal kingdom
They do not have a backbone (invertebrate)
They have a skeleton on the outside of the body (exoskeleton)
A segmented body with jointed legs and are symmetrical along their length

Question 3

Give some examples of Arthropods

Answer 3

Insects (butterflies, ants etc)
Arachnids (spiders, mites, scorpions)
Chilopods (centipedes)
Diplopoda (millipedes)

Question 4

What are the three processes involved with growth?

Answer 4

Cell division
Synthesis of new structures from raw materials
Cell expansion

Question 5

What sort of growth pattern do vertebrates show?

Answer 5

Vertebrates tend to start with slow growth, then speed up the rate of growth before slowing down again

Question 6

What sort of growth pattern do arthropods show?

Answer 6

Arthropods show a stepped growth pattern

Question 7

What factors determine growth in plants and animals?

Answer 7

External factors include temperature, diet and light . Growth is determined internally by hormones

Question 8

What are meristems and where are they found?

Answer 8

Meristems are actively dividing cells found in plants at the tip of the roots and shoots

Question 9

What is secondary growth in plants?

Answer 9

It is the increase in girth

Question 10

What does an arthropod do when it grows bigger?

Answer 10

It sheds

Question 11

When a cell divides what are the cells called that are produced?

Answer 11

Progeny cells or daughter cells

Question 12

What is the difference between the growth of a multicelled organism and a single celled organism?

Answer 12

Multicellular organisms grow in size whereas single celled organisms grow in numbers

Question 13

Define the term mutation?

Answer 13

A change in the genes of a plant or animal that causes it to become different

Question 14

What is asexual production?

Answer 14

Only one parent is needed to produce offspring

This is what single celled organisms do

Question 15

What is sexual reproduction? The

Answer 15

Two parents are required to produce offspring

Question 16

What is the process that most prokaryotic cells divide?

Answer 16

Binary fission

Reproduction of a cell by division into two approximately equal parts

Question 17

The process of cell division, binary fission, in prokaryotes is much simpler than the process of cell division in eukaryotes because the cells are simpler.
In what way are prokaryotic cells simpler than eukaryotic cells?

Answer 17

Prokaryotic cells do not have internal organelles

Question 18

What is meant by the term cell cycle?

Answer 18

It is a series of processes that take place in a cell

Question 19

How long can a cell cycle of a eukaryote take?

Answer 19

Anywhere from a few hours to many weeks

Question 20

What factors does the rate at which a cell proceeds through the cycle depend on?

Answer 20

Type of organism
The type of cell
It’s size
Environment in which it is growing

Question 21

On average how long does it take cells to divide on

A plant
The gut of a mouse
Human skin?

Answer 21

A plant- 12 hours
Gut of a mouse- 17 hours
Human skin- 24 hours

Question 22

How many phases are there in a eukaryote cell cycle?

Answer 22

4 phases

Question 23

What are the 4 phases of a eukaryote cell called?

Answer 23

G1 (gap1) phase
S phase (synthesis)
G2 (gap 2) phase
M phase (mitosis)

Question 24

What are the first three phases of a eukaryote cell cycle collectively known as?

Answer 24

Interphase

Question 25

What happens in the G1 phase of a eukaryote cell cycle?

Answer 25

The first phase of the cell cycle The cell grow Increasing the number of organelles Prepares for DNA synthesis

Question 26

What happens in the S phase of a eukaryote cell cycle?

Answer 26

The second phase The DNA is replicated By the end of this phase the cell has copied each chromosome

Question 27

What happens in the G2 phase of a eukaryote cell cycle?

Answer 27

The cell prepares for division in the G2 phase

Question 28

What happens in the M phase of a eukaryote cell cycle?

Answer 28

It is a relatively short but highly dynamic phase It is known as mitosis The chromosomes condense and 2 sets of chromosomes segregate equally into 2 separate nuclei The cytoplasm divides, to form 2 completely separate daughter cells.

Question 29

What is cytokinesis?

Answer 29

It is when the cytoplasm of a cell divides during the mitosis phase of a eukaryote

Question 30

What do cells do when they divide?

Answer 30

They can immediately re enter the cycle and divide again, or they can exit the cycle to a resting phase called G0 where they will remain until stimulated to enter G1 again

Question 31

What is mitosis?

Answer 31

It is the last phase of cell division for a eukaryote | It involves the two set of chromosomes condensing and then segregating equally into two separate nuclei

Question 32

How many pairs of chromosomes do humans have ?

Answer 32

23

Question 33

How many chromosomes do humans have ?

Answer 33

46 | 23 pairs

Question 34

What are autosomes?

Answer 34

Any chromosome that is not a sex chromosome | Look similar

Question 35

What is a sex chromosome?

Answer 35

It is the chromosome that determines whether you are male or female

Question 36

What is a homologous chromosome?

Answer 36

Pair of chromosomes | That contain hereditary genes one from the mother and one from the father

Question 37

What are the 5 stages of mitosis?

Answer 37

``` Prophase Metaphase Anaphase Telophase Cytokinesis ```

Question 38

At what stage of the cell cycle does DNA replication occur?

Answer 38

S (synthesis) phase

Question 39

When does the prophase of mitosis start?

Answer 39

When the chromosome condense prophase starts

Question 40

At what stage do chromosomes become visible under a microscope

Answer 40

Prophase | The first stage of mitosis

Question 41

What is a diploid cell?

Answer 41

A cell that contains homologous chromosomes | Pair of chromosomes - one from the mother- one from the father

Question 42

When a chromosome is replicated in S phase how does it appear?

Answer 42

Each chromosome consist of an identical pair of chromatids connected at the centromere

Question 43

What happens in the metaphase of mitosis?

Answer 43

At metaphase the chromosomes line up with their centromeres aligned at the equator of the cell

Question 44

What happens in the anaphase of mitosis?

Answer 44

At anaphase the centromere of each chromosome divides and he two chromatids are drawn towards opposite piles of the cells. The delayed chromatids are now referred to as chromosomes

Question 45

During anaphase the chromatids are pulled to the outer part of the cell, what is the mechanism that drives the movement of the chromatids

Answer 45

The spindle microtubules to which each chromatid is attached shorten, thereby drawing the chromatid towards the pole

Question 46

What happens in telophase of mitosis of a cell?

Answer 46

At telophase the spindle disassembles. A new nuclear membrane develops around each of the two groups of chromosomes

Question 47

What is the final result of mitosis and cytokinesis?

Answer 47

Two diploid cells, each genetically almost identical to the original parent cell

Question 48

Define the term centromere?

Answer 48

It is the point of attachment of a chromatid

Question 49

What happens in prophase of mitosis?

Answer 49

Chromosomes condense 2 homologous chromosomes pair Nuclear membrane breaks down Spindle microtubules attach to centromere

Question 50

What is a chromatid?

Answer 50

One of two identical strands into which a chromosome splits during mitosis

Question 51

What is the mechanism that drives the movement of chromatids?

Answer 51

The spindle microtubules to which each chromatid is attached shorten, thereby drawing the chromatid towards the pole

Question 52

How do prokaryotic cells divide?

Answer 52

Prokaryotic cells divide (reproduce) asexually by the process of binary fission and this results in reproduction of the parent cell into identical progeny cells