F211 Cell Division, Cell Diversity, Cellular Organisation

Question 0

Interphase

Phases

Answer 0

Growth 1
Synthesis
Growth 2

Question 1

Cell Cycle

Answer 1

Nuclear division, mitosis, is only a very small part of the cycle, a third of the other three phases
Growth 1, Synthesis, Growth 2, take up a third each of the rest of the cycle

Question 2

Interphase

Growth 1

Answer 2

First and longest growth stage
Organelles produced
Cytoplasm volume increases

46 chromosomes

Question 3

Interphase

Synthesis

Answer 3

Chromosome replication
DNA content doubles

92 chromosomes

Question 4

Interphase

Growth 2

Answer 4

Second growth phase
Cytoskeleton breaks down
Checks that the copied DNA is correct

Question 5

Mitosis

Phase

Answer 5

Prophase
Metaphase
Anaphase
Telophase

Question 6

Prophase

Answer 6

Chromosomes shorten and thicken, coil around histones
Nuclear envelope breaks down and disappears
Centriole divides in two
Each daughter centriole moves to the opposite poles of the cell
Centrioles organise the spindle, a 3D structure made of microtubles

Question 7

Metaphase

Answer 7

Chromosomes move to the central region of the spindle, the equator
Each chromosome becomes attached to a spindle thread by its centromere

Question 8

Anaphase

Answer 8

Replicated chromatid pairs separate when the centromere holding them together splits
Spindle fibres shorten pulling the sister chromatids away from each other towards the poles
They assume a V shape because they are pulled by their centre

Question 9

Telophase

Answer 9

The separated chromatids reach the poles of the cell
A new nuclear envelope forms around each set of chromosomes
The spindle breaks down and disappears
The chromosomes uncoil

Question 10

Cytokinesis

Answer 10

Cell division

Takes place after mitosis

Question 11

Cytokinesis

In Animal Cells

Answer 11

The membrane constricts around the middle of the cell
A ring of protein filaments bound to the surface of the cell membrane contract until the cell is divided into two, actin and myosin
The daughter cell is genetically identical to the parent cell

Question 12

Cytokinesis

In Plants

Answer 12

Only happens at meristems

A new cell wall plate is synthesised between the two new cells where the spindle was

Question 13

Homologous Pair of Chromosomes

Answer 13

Chromosomes that have the same genes at the same loci
Pair up during meiosis
One chromosome from each parent
Made up of genes that code for the same thing

Question 14

Purposes of Mitosis

Answer 14

Produces cells which are genetically identical to the parent and can therefore perform the same function. This is used for:
Asexual Reproduction
Growth
Repair
Replacement

Question 15

Purpose of Mitosis

Asexual Reproduction

Answer 15

Single called organisms divide to produce two daughter cells that are separate organisms
Some multicellular organisms produce offspring from parts of the parent

Question 15

Purpose of Mitosis

Repair

Answer 15

Damaged cells need to be replaced by new ones that are identical so they can do the same function

Question 16

Purpose of Mitosis

Growth

Answer 16

Multicellular organisms grow by producing new extra cells

Each new cell is genetically identical to the parent so can perform he same functions

Question 17

Purpose of Mitosis

Replacement

Answer 17

Red blood cells and skin cells are replaced by new ones

Question 18

Budding in Yeast

Answer 18

Growth 1
Synthesis - budding begins as DNA replicates
Growth 2
Mitosis
Cytokinesis, the bud separates from the parent cell

Question 19

Products of Meiosis

Answer 19

4 gametes
Not genetically identical
Contain half the genetic material / number of chromosomes

Question 20

Stem Cell

Answer 20

Undifferentiated cells that are capable of becoming differentiated to a number of possible cell types
Totipotent

Question 21

Differentiation

Definition

Answer 21

The development and changes seen in cells as they mature to form specialised cells

Question 22

Differentiation

Erythrocytes (Red Blood Cells)

Answer 22

Produced form undifferentiated cells in bone marrow
Lose their nucleus, mitochondria, golgi body and rough endoplasmic reticulum
Packed full of protein haemoglobin
Shape changes to be bio concave
Allows them to triplet oxygen efficiently in the blood

Question 23

Differentiation | Neutrophils

Answer 23

Differentiated from stem cells in the bone marrow Produce enormous numbers of lysosomes To produce enzymes to digest engulfed microorganisms

Question 24

Differentiation | Phloem Sieve Tubes

Answer 24

Differentiated from cambium Cells elongate and line up end to end to form a long tube Ends of cells do not break down completely but form sieve plates which allow the movement of materials up or down the tubes

Question 25

Differentiation | Xylem Vessels

Answer 25

Differentiated from cambium Small cells that elongate Walls become reinforced and waterproofed by lignin which kills the contents of the cell Ends of the cell break down so they become a continuous long tube with a wide lumen Able to transport water and minerals and helps to support the plant

Question 26

Cambium

Answer 26

A type of meristem cell

Question 27

Requirements for Photosynthesis

Answer 27

Light A supply of water A supply of carbon dioxide The presence of chlorophyll

Question 29

Specialisation | Erythrocytes

Answer 29

Contains Haemoglobin for oxygen to bind to Few organelles to make space for haemoglobin Bio concave shape increases surface area to allow more often to bind

Question 30

Specialisation | Neutrophils

Answer 30

Large numbers of lysosomes to produce enzymes to digest engulfed microorganisms

Question 31

Specialisation | Epithelial Cells

Answer 31

Squamous - flattened cells reduces distance for diffusion, able to form a smooth flat surface so they are ideal for the insides of tubes where fluids can pass easily over them Ciliated- covered in tiny projections called cilia which are able to waft substances (e.g. mucus) past the cell

Question 32

Specialisation | Sperm Cells

Answer 32

Many a mitochondria for energy from respiration so they can move more Specialised lysosome, acrosome, in the head that released enzymes onto the outside of the egg allowing the sperm to penetrate and fertilise the egg Small long and thin to ease their movement Single long undulipodium (tail) to propel the sperm towers the egg

Question 33

Specialisation | Palisade Cells

Answer 33

Contain lots of chloroplasts to collect more light energy

Question 34

Specialisation | Root Hair Cells

Answer 34

Hair like projections increases surface area so that more water and minerals can enter the cell Large vacuole to store minerals

Question 35

Specialisation | Guard Cells

Answer 35

Appear in pairs on the lower epidermis of leaves Contain chloroplasts and cell walls contain spiral thickenings of cellulose When water moves in the cells become turgid and because of the spirals only the outer walls stretch Two guard cells bulge at both ends so the pore, stomata, opens

Question 36

Tissue | Definition

Answer 36

A group of similar cells that work together to perform a particular function

Question 37

Organ | Definition

Answer 37

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

Question 38

Organ System | Definition

Answer 38

A number of organs working together to perform an overall life function