L2: Cells, tissues & homeostasis

Question 1

identify the organisation of living things

Answer 1

atoms -> molecule -> macromolecule -> organelle -> cell -> tissue -> organ -> organ system -> organism

Question 2

cells are divided into two categories (identify & describe)

Answer 2

prokaryotes (bacteria & archaea)
- simple, DNA floating around
eukaryotes (plants, fungi & animals)
- complex, DNA in a nucleus

Question 3

identify & describe the components of a eukaryote cell

Answer 3

plasma membrane (semipermeable casing)
cytoplasm & cytoskeleton (provide structure)
nucleus (holds DNA)
endomembrane system (surround nucleus, internal cell communication)
mitochondria (produces energy)

Question 4

what is apart of the endomembrane system?

Answer 4

endoplasmic reticulum
golgi complex
lysosomes

Question 5

mitochondria contains DNA that is only passed through the . . . line

Answer 5

maternal

Question 6

what are cilia, flagella, & pseudopodia?

Answer 6

specialised features in a eukaryote cell for cell locomotion

Question 7

what part of eukaryote cells aid in absorption of ingested food water & how?

Answer 7

microvilli - increased surface area

Question 8

identify the part in a eukaryote cell that regulates selective movements of substances

Answer 8

the tight junction

Question 9

what is the purpose of desmosomes in a eukaryote cell?

Answer 9

mediates cell-to-cell contact

Question 10

identify 3 types of endocytosis (cell eating)

Answer 10

phagocytosis
pinocytosis
receptor-mediated endocytosis

Question 11

describe the process of phagocytosis

Answer 11

occurs in simple animals
membrane of the cell wraps around object, enclosing it in a vesicle. lysome carries enzymes to break down the object

Question 12

describe the process of pinocytosis

Answer 12

phagocytosis with receptors
molecule interacts with a particular receptor on cell membrane, forming a caveolae around the molecule

Question 13

what is transcytosis?

Answer 13

the molecule is moved to another part of the cell where it is needed (during pinocytosis)

Question 14

identify the type of endocytosis that involves the binding of large molecules

Answer 14

receptor-mediated endocytosis

Question 15

what is mitosis?

Answer 15

a form of cell division, resulting in two identical daughter cells

Question 16

identify the 4 phases of mitosis

Answer 16

prophase: gathering of chromosomes in nucleus
metaphase: spindles attach to 2 parts of chromosomes
anaphase: separation of spindles
telophase: creation of own nuclei & replicating chromosomes

Question 17

what is apoptosis?

Answer 17

programmed cell death, allowing cells to turnover.

Question 18

identify the types of cells in animals

Answer 18

sex cells
skin/epithelial cells
muscle cells
blood cells
nerve cells
fat cells

Question 19

what are tissues?

Answer 19

groups of cells specialised for a function

Question 20

describe the function of the 4 types of tissue & name an example for each

Answer 20

connective (bone, blood, cartilage, tendons)
- binds & supports other tissue
nervous (nerves, brain)
- senses stimuli & transmits signals throughout the organism
epithelial (skin, intestinal linings)
- closely joined cells covering the body
muscle
- contract in response to nerve signals
- helps with locomotion

Question 21

identify the 3 types of muscle tissue & name an example for each

Answer 21

smooth muscle (digestive tract & involuntary body movements)
cardiac muscle (heart contractions)
skeletal muscle or striated (voluntary movements)

Question 22

how does muscle tissue work?

Answer 22

slides past eachother to contract
attached in antagonistic pairs (contracting/relaxing muscle)

Question 23

what are the different types of symmetry in animal body plans?

Answer 23

spherical
radial
bilateral

Question 24

what is the purpose of skeletons?

Answer 24

provides support & locomotion

Question 25

identify the 3 kinds of skeletons

Answer 25

hydrostatic: no firm base, fluids enclosed in cavity exoskeleton: protective outer ridge skeleton endoskeleton: internal bone or cartilage skeleton

Question 26

what is homeostasis?

Answer 26

self-regulating process of maintaining an internal balance, despite external conditions

Question 27

what is positive & negative feedback?

Answer 27

negative feedback reduces the stimulus to a stable state positive feed back amplifies the stimulus

Question 28

what is acclimatisation?

Answer 28

adjusting to changes in external environment

Question 29

what is thermoregulation?

Answer 29

the process of maintaining internal temperature within a range tolerable for systems to function

Question 30

what is endothermic?

Answer 30

generating heat by metabolism allows animals to be active at greater range of temperatures, but more energetically expensive

Question 31

what is ectothermic?

Answer 31

gaining heat from external sources tolerates fluctuating temperatures more

Question 32

how is heat exchanged between organisms?

Answer 32

radiation (waves) evaporation (sweating) convection (water & air) conduction (direct contact)

Question 33

provide 5 examples of different adaptations for thermoregulation

Answer 33

insulation reduces heat flow between animal & environment circulatory adaptations may enhance or constrict blood flow cooling by evaporative heat loss behavioural responses adjusting metabolic heat production (shivering or non shivering thermogenesis)