Characteristics, variety, level of organisation and cell structure in living organisms

Question 1

Characteristics of living organisms

Answer 1

Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition
+ Control (of internal conditions)

Question 2

Plant features and cell structure

Answer 2

Plants: Multicellular, cells contain chloroplasts so can photosynthesize; cellulose cell walls, store carbohydrates as starch/sucrose
Cell structure: Cell wall, cell membrane, cytoplasm, chloroplasts, nucleus, mitochondria, permanent vacuole, ribosomes
Eukaryotic

Question 3

Animal features and cell structure

Answer 3

Animals: Multicellular, no chloroplasts so cannot photosynthesize; no cell walls; usually have nervous coordination, store carbohydrate as glycogen, able to move from place to place
Cell structure: Cell membrane, cytoplasm, nucleus, mitochondria, ribosomes
Eukaryotic

Question 4

Fungi features and cell structure

Answer 4

Fungi: Some multi, some unicellular. Cannot photosynthesize, body usually organised into a mycelium made from hyphae(thread like structures) that contain many nuclei; chitin cell walls, feed by secreting extracellular digestive enzymes onto food material and absorption of the organic products (saprotrophic nutrition); some may store carbohydrates as glycogen
Cell structure: Cell wall, cell membrane, cytoplasm, nucleus, mitochondria, ribosomes
Eukaryotic

Question 5

Protoctist features and cell structure

Answer 5

Protoctists: Microscopic unicellular organisms; different features resembling different types of organisms, some animal some plant
Cell structure: Cell membrane, cytoplasm, nucleus, mitochondria, ribosomes, some (food vacuoles, chloroplasts), contractile vacuole
Eukaryotic

Question 6

Bacteria features and cell structure

Answer 6

Bacteria: Microscopic unicellular organisms; contain plasmids(small circular loops of DNA that contain genes, lack of nucleus but a circular chromosome of DNA; some can photosynthesize but most feed off other living or dead organisms
Cell structure: Cell wall, cell membrane, cytoplasm, circular loop of DNA, ribosomes, plasmids

Question 7

Pathogen definition:

Answer 7

Any microorganism that causes disease in another organism
They include: Bacteria, Fungi, Protoctists, Viruses - all viruses are pathogenic

Question 8

Virus features and cell structure

Answer 8

Viruses: Not living organisms; small particles smaller than bacteria; parasitic and can only reproduce inside living cells; they infect every type of living organism. Wide variety of shapes and sizes; no cellular structure but have a protein coat and DNA or RNA

Question 9

Level of organization in organisms, starting from organelles

Answer 9

organelles - A component within a cell that carries out a specific task
cells - Basic functional and structural units in a living organism
tissues - A group of cells of similar structure working together to perform a particular function
organs - A group of different tissues working together to perform a particular function
organ systems - A group of different organs with related functions, working together to perform body functions within the organism

Question 10

Nucleus function

Answer 10

Contains genetic material in chromosomes (DNA)
Controls cell division

Question 11

Cytoplasm function

Answer 11

Supports cell structures
Site of many chemical reactions
Contains water and many solutes

Question 12

Cell membrane function

Answer 12

Holds the cell together
Controls substances entering and leaving the cell

Question 13

Cell wall function

Answer 13

Gives the cell extra support and defines it shape

Question 14

Chloroplast function

Answer 14

Site of photosynthesis
Chlorophyll pigments absorb light energy for the reaction to occur

Question 15

Vacuole function

Answer 15

Contains cell sap
Used for storage of certain material
Also helps support shape of cell

Question 16

Mitochondria function

Answer 16

Site of aerobic respiration, providing energy for cell

Question 17

Ribosome function

Answer 17

Site of protein production in protein synthesis

Question 18

Differences between animal cell and plant cell

Answer 18

Plant cells have a cell wall, chloroplasts, and a permanent vacuole while animals do not

Question 19

Bacterial cell structure

Answer 19

Cell membrane
Cell wall (peptidoglycan)
Circular loop of DNA
Plasmids
Ribosomes

Question 20

Virus structure

Answer 20

DNA/RNA
Envelope
Protein coat
(they are very small)

Question 21

Stem cell definition

Answer 21

An undifferentiated cell capable of dividing and developing into different types of specialised cells

Question 22

Importance of cell differentiation

Answer 22

Cell differentiation is how cells develop the structure and characteristics needed to be able to carry out their functions

Question 23

Specialised cell definition

Answer 23

Cells that have developed certain characteristics that allow them to perform particular functions
These differences are controlled by genes in the nucleus

Question 24

Embryonic stem cell

Answer 24

Found in the inside layer of an embryo
Undifferentiated / unspecialised
All the different types of specialised cells found in the body can be produced

Question 25

Adult stem cells

Answer 25

Found in bone marrow, skin, other organs (e.g. liver), and umbilical cord blood Limited ability to differentiate / partially specialised Bone marrow: Cells in blood e.g. red blood cells can be produced Skin: Cells found in different layers of the skin, hair follicles can be produced Other organs: Cells found in these organs can be produced Umbilical cord blood: Cells from the blood, muscle and nerve tissue can be produced

Question 26

Meristem cells

Answer 26

Found in tips of roots and shoots (growing region of a plant) Fully undifferentiated One cell has the ability to divide to produce a whole new plant

Question 27

Treatment of diabetes using stem cells

Answer 27

Problem: Inability of pancreas to produce insulin to control blood sugar levels Stem cells could be differentiated into insulin-producing pancreatic cells which are transplanted onto the patient's body Source: Stem cell donors or therapeutic cloning

Question 28

Treatment of paralysis using stem cells

Answer 28

Problem: Damage to nerve cells in the brain or spinal cord, preventing signals from the brain reaching muscles in parts of the body resulting in loss of movement Stem cells could be differentiated into nerve cells (neurones) which are transplanted into the damaged region of the nervous system Source: Stem cell donors or therapeutic cloning

Question 29

Therapeutic cloning

Answer 29

An embryo is produced with the same genes as the patient A 5-day old embryo is the best source for embryonic stem cells Stem cells from embryos are not rejected by the patients body

Question 30

Advantages of using stem cells

Answer 30

Great potential to treat a wide variety of diseases Organs developed from a patients own stem cells reduces the risk of organ rejection and the need to wait for an organ donation Adult stem cells are already used successfully in a variety of treatments

Question 31

Disadvantages of using stem cells

Answer 31

Stem cells cultured in a lab could become infected with a virus which could be transmitted to the patient There is a risk of cultured stem cells accumulating mutations that can lead to them developing into cancer cells Lack of peer-reviewed clinical evidence of the success of stem cell treatments Ethical issue of sourcing stem cells from unused embryos Ethical issue of creating embryos through therapeutic cloning then destroying them