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Flashcards in Chapter 5 Deck (22):
1

Homeostasis

state, maintenance of a constant internal environment(blood plasma and extracellular fluid) within narrow limits

2

Flowchart

Signal, reception, transduction, effector, cellular response

3

Endocrine signalling

Ligands secreted into the bloodstream

4

Paracrine signalling

Secreted in the extracellular fluid to neighbouring cells

5

Autocrine signalling

Secreted by a cell that receives the signal

6

Contact-dependent signalling

direct membrane contact (gap junctions, plasmodesma, mobile)

7

Complementary

Ligands and Receptor proteins must be complementary, receptor for every ligand

8

Hydrophobic hormones (steroid)

Signalling molecule binds to its receptor (cytoplasm), the 3D shape of the receptor is altered, activating the receptor, ligand-receptor complex move into the nucleus and bind with DNA, regulate gene expression, proteins made
Long-lasting

9

Hydrophilic hormones (amino acid derivatives and peptide)

Signalling molecule is the first messenger, binds to protein receptor, the 3D shape of the receptor is altered and it activates an enzyme which catalyses the second messenger, enzyme cascade (signal is amplified), nucleus, proteins are made
Short-lived

10

Positive/negative feedback

Oppsoing stimulus to maintain homeostasis
Increasing stimulus

11

Endocrine system

Secretions directly into internal environment (extracellular fluid)

12

Exocrine glands

Secretions that pass along ducts to the external environment (tears, sweat)

13

Hormone

A chemical messenger secreted by endocrine cells that often travels through the bloodstream to a target organ where it effects a response

14

Insulin
Glucagon
ADH
Thyroxin

Produced by beta cells, uptake of glucose, stored as glycogen, peptide
Produced by alpha cells, breakdown of glycogen releasing glucose into bloodstream, peptide
Prevents extra water loss, higher reabsorption of water, high urea concentration and low urine volume, protein
Increased metabolic rate and heart rate, promotes growth, amino acid derivative

15

Neurons

Nucleus, cell body, dendrites, axon, myelin sheaths, schwann cell, axon terminals, synapse

16

Apoptosis and Necrosis

Natural programmed cell death, maintain cell numbers, defence against damaged/dangerous cells (virus infected, DNA damaged), depend on caspases
unprogrammed cell death, due to external factors

17

CNS and PNS

Brain and spinal cord
sensory (photoreceptors, pain receptors, chemoreceptors, thermoreceptors) and motor neurons

18

Process of Nervous system

Stimuli
Receptors of sensory neurons detect change
Travels to CNS
Interneurons
Motor neurons (neurotransmitters diffuse to receptors on muscle fibres, enzyme inactivates neurotransmitter)
Electrical signal through neurons, chemical in between

19

Pheromone

chemical ligands released by one animal that effects a physiological or behavioural change in another animal (same species)
Animals have a vomeronasal organ that senses pheromones (different nerve pathway)
Types: trail (ants), alarm, territorial (urine), sex (indicates ready to mate)

20

Cytokines

Aid cell to cell communication in immune responses and stimulate the movement of cells toward sites of inflammation, infection or trauma

21

Plant hormones

Ligands produced in one part of a plant that effects a physiological or biochemical change in a specific target tissue (made in meristems and travel through xylem, phloem, air, cell-to-cell)
Not species specific

22

Auxin
Cytokinins
Gibberellins
Abscisic acid
Ethylene

Enlargement, elongation of plant cells
cell reproduction
Elongation and cell reproduction
Dormancy
Ripening