Biology of Animals exam

Question 1

4 CHARACTERISTICS OF ANIMAL KINGDOM

Answer 1

eukaryotic cell with nucleus, without cell wall
CaCO3 skeleton
glycogen, specific sterole biosynthesis
small mitochondrial genome

Question 2

Chemical composition, chemical and mechanical characteristics of CHITIN, which animals

Answer 2

Polymer of N-acetyl-D-glucosamine residues (beta (1,4) linkages)
Weak solubility in common organic and diluted aqueus solvents - highly hydrophobic & biodegredable
White inelastic, rigid, resilient, tough (esp. with CaCO3)
Crustaceans, insects, arthropods, molluscs

,

Question 3

Chemical composition, chemical and mechanical characteristics of COLLAGEN, which tissues and organs

Answer 3

3 polypeptide strands twisted into a triple helix, stabilized by hydrogen bonds (2 identical alpha1 chains and additional alpha2 chain). Regular arrangement of aa: Gly-X-Pro/Gly-X-Hyp - Gly needs to be on every 3rd position
Long, fibrous protein, has great tensile strength, gives cells structure
Bones, cartilage, skin, blood vessels, the gut, dentin, muscle tissue

Question 4

Strucutre of SPERM CELL and direction of its movement; exceptions

Answer 4

Head (contains genetic material for fertilisation) & acrosome (contains enzymes - sperm can penetrate) + midpiece (mitochondria), tail (enables the sperm to move)
Straight, zig-zag, vibrating, non-motile
(testicle - vibrating; fresh ejaculation - zig-zag; female reproduction - erradic)
Decapods, diplopods and mites (not flagellated sperm)

Question 5

PORIFERA: SKELETON

Answer 5

Bodies full of pores and channels (allow wter to circulate through). They have unspecialized cells that can transform into other tyoe. They don’t have nervous, digestive or circulatory system. They hav one common exhalant. The inner surface is covered with choanocytes; cells with cylindrical or conical collars surrounding one flagellum.
Mesophyl (jelly-like substance from collagen) functions as endoskeleton. They have spiclues (core of organic material around which is deposited Ca or silica - siliceous or calcareous) and spogin fibres

Question 6

Photosynthetic symbionts: taxa, benefits and threats

Answer 6

Porifera and Cnidaria with microalgae or cyanobacteria
Benefits: symbiosis extends the energy resources available to reef organisms - photosynthetic products are released to the sponge
Risk: elevated T or irradiance can lead to production of reacive oxygen species; damage to membrane and proteins, and “bleaching” (stressed corals expel the symbiotic algae)

Question 7

ACETYLCHOLINE: structure, function, tissues, taxa

Answer 7

Ester of acetic acid and choline
Neurotransmitter (motor neurons release it in order to activate muscles)
Motor neurons, parasympathetic nervous system, brain
Ctenophora and Chelicerata

Question 8

Bioluminiscence: taxa, function

Answer 8

Cnidaria, fireflies, jellyfish, some fish

Distract or repel predators, attrat prey, communicate within species, camouflage, attract mates

Question 9

Protein venoms: taxa, way of delivery

Answer 9

Chelicerata (Aranea and Scorpiones), Cnidaria, Chilopoda
(Aranea) They use the fang, which is retracted inside the basal segment. When the spider catches its prey, it swings the fangs out into the animal’s body and squeezes out the venom.
(Scorpions) They use their pincers to grasp their prey and then they arch their tail over their body to drive their stinger into the prey to inject the venom. The stinger lies at the tip of the scorpion’s tail and it features the bulb, where the venom is produced and stored.
(Cnidaria) They have nematocytes (stinging cells) that contain a tubule with a capsule of venom, when stimulated it is averted and strikes the prey/predator. Then it penetrates the outer membrane and delivers the venom.
(Chilopoda) They have forcipules, stinger-like appendages, that pierce the skin and inject venom into the wound.

Question 10

Silk: composition and properties, which taxa

Answer 10

Aranea
2 proteins: fibroin and sericin - high contents of glycine and alanine. Pyrrolidine (keeping the silk moist)
High tensile strength and extensibility, adhesive properties, antimicrobial properties (potassium hydrogen phosphate - acidic antimicrobial)

Question 11

Ticks (Acari): dangerous compounds and transferred microorganisms

Answer 11

Produce a neurotoxin in the salivary gland

Bacteria (Borrelia) - Lyme disease + virus (meningitis and Tick-Borne encephalitis)

Question 12

External digestion: taxa, which food

Answer 12

Aranea - insects and even other spiders
Asteroida - clams, oysters, mussels, snails and injured fish (stomach out, will enclose and turn soft tissue to liquid, return to the body of the sea star) & decaying tissues

Question 13

Tracheal system: structure, function, in which taxa

Answer 13

After passing through a spiracle, air enters a longitudinal tracheal trunk, eventually diffusing throughout a complex, branching network of tracheal tubes that subdivides into smaller and smaller diameters and reaches every part of the body. At the end of each tracheal branch, a special cell (the tracheole) provides a thin, moist interface for the exchange of gasses between atmospheric air and a living cell.
Oxygen in the tracheal tube first dissolves in the liquid of the tracheole and then diffuses across the cell membrane into the cytoplasm of an adjacent cell. Carbon dioxide, diffuses out of the cell and out of the body.
Taxa: Chelicerata, Myriapoda, Insecta

Question 14

Centipedes: venom, composition and action

Answer 14

Composition: serotonin and histamine, serine protease, glycoside hydrolases and other enzymes
Action: the venom can be myotoxic (effect on muscles), cardiotoxic and neurotoxic. Venom causes pain and swelling in the area of the bite and may cause other reactions throughout the body. It interferes with ion channels within nerve cells.

Question 15

Venomous animals with parental care, how they defend their progeny

Answer 15

Chilopoda guard their eggs for 2 weeks, during that time the female is very aggressive and does not feed.
Scorpions give birth to live larvae and the mother carries them on her back.
Spiders build some kind of protective cover for the eggs, some even take care of the young spiders after they have hatched. Some of them lay a special supply of eggs (trophic eggs) for the spiderlings to eat

Question 16

Millipedes: defence mechanisms, compounds

Answer 16

Repugnatorial glands (secretion consist of topical irritants, repellents, antifeedants (alkaloids, phenols, terpenoids, benzoquinones or hydrogen cyanide that can be fatal)). 
Ability to roll into a smooth, resistant sphere or coil
Spikey projections that may deter soft-mouthed predators

Question 17

Chromosomal sex determination types

Answer 17

Drosophila: female is XX and male is XY (male heterogamety) - sex is determined by the ratio of X:a (number of X chromosomes relative to the number of autosomes)
Abraxas: female is WZ, male is ZZ (female heterogamety)
Hymenoptera: female is AA, male is A (haploid)

Question 18

Juvenile hormone: function, way of use against pests

Answer 18

The juvenile hormone makes the cuticle grow
Benzoyl hydrazine analogs act as a native molting hormone and bind to the ecdysone receptor - activating certain transcription factors - expression of molt-related genes. The larvae goes into a precocious incomplete molt which is lethal