Exam 4 Flashcards
characterizes unicellular organisms
protoplasmic grade
an aggregation of cells that are functionally differentiated
cellular grade
an aggregation of similar cells into definite patterns or layers and organized to perform a common function
tissue grade
an aggregation of tissues into organs
tissue-organ grade
organs work together to perform some function, producing the highest level of organization
organ-system grade
Any plane passing through center divides body into mirrored halves
spherical symmetry
Body can be divided into similar halves by more than 2 planes passing through the longitudinal axis.
radial symmetry
What are some characteristics of radial symmetry?
Organism has no anterior or posterior end and can interact with surroundings in all directions
A form of radial symmetry in which part of the organism is single or paired rather than radial
biradial symmetry
Organism can be divided along a single plane into two identical portions
bilateral symmetry
The differentiation of a head region with concentration of nervous tissue and sense organs
cephalization
What are some characteristics of bilateral symmetry?
Organisms are better suited for directional movement and they are associated with cephalization.
Water moves through cell walls
apoplast
Water moves from protoplast to protoplast via plasmodesmata
symplast
Water moves from protoplast to protoplast crossing plasma membranes
transcellular
How does the active transport of protons aid in the cotransport of molecules against their concentration or electrical gradient?
ATP activated proton pumps force more protons on one side of the membrane, creating a pH gradient. Molecules that fit the same cotransport enzyme can then bind at the same time as the protons and enter the cell
The movement of liquid in response to a pressure gradient
bulk flow
How does bulk flow differ from osmosis?
Unlike osmosis, bulk flow is independent of solute concentration.
The loss of water vapor from leaves and other aerial parts of the plant
transpiration
Transpiration creates a negative pressure that pulls water upwards from the roots
cohesion-tension hypothesis
How does transpiration affect leaf temperature?
Transpiration results in evaporative cooling, which can lower a leaf’s temperature. This prevents the leaf from reaching temperatures that could denature enzymes.
What are the basic steps involved in the opening and closing of stomata?
- Proton pump is activated
- K+ moves into guard cells
- Negative osmotic pressure pulls water into guard cells
- Turgid guard cells=open stomata
What morphological features limit transpirational water loss? How do they do this?
Leaves have stomata which can open and close due to guard cells. They also have a waxy cuticle which limits water loss on the parts of the leaf that don’t have stomata.
Describe essential elements concerning plants?
required to complete life cycle, part of an essential molecule, and there are 17 common to all plants
Describe beneficial elements?
essential for a limited number of species and involved in specialized pathways or symbioses
What symptoms would a phloem-mobile element deficient plant have? (This may not be a good question)
chlorosis, or yellowing of the leaves
What are some of the symbiotic relationships that help plants obtain mineral nutrients more efficiently?
root nodules and mycorrhizae
What modes of action are used by plant hormones to stimulate growth and development?
increasing cell elongation, increasing the rate of cell division, and/or influencing differentiation
What is the acid growth hypothesis?
Proton pumps activate expansins in the cell wall, polysaccharide cross-links are cleaved which loosens the cellulose, and ions move into the cell which decreases osmotic pressure so water follows to increase pressure potential
Explain the series of experiments that helped botanists understand the role of auxin in phototropism.
It was discovered that the tip of the stem is what senses light. Then, it was thought that the signal for phototropism was mobile, but that was proven wrong(?) Finally, a shoot tip was grown on an agar block so the chemical would diffuse into the agar block. The block would then stimulate growth. By placing blocks on only one side of the shoot tip, it was proven that growth is actually stimulated on the dark side and auxin pushes growth toward the sun.
What hormones are involved in maintaining dormancy or stimulating germination?
Absciscic acid maintains dormancy in buds and seeds, gibberellic acid stimulates germination.
What are the five grades of organization?
protoplasmic grade, cellular grade, cell-tissue grade, tissue-organ grade, organ system grade
Which type of symmetry is rarely found in animals?
spherical symmetry
Reproduction where an egg develops without being fertilized
parthenogenesis
Each individual in a species has both male and female reproductive systems
hermaphroditism
What are the main steps involved in spermatogenesis?
Diploid spermatogonia enlarge and become primary spermatocytes. Diploid primary spermatocytes divide by meiosis I and produce 2 secondary spermatocytes. Haploid secondary spermatocytes divide by meiosis II to total 4 spermatids. Haploid spermatids transform into 4 sperm.
What are the main steps involved in oogenesis?
Diploid oogonia initially increase in number by mitosis, then stop dividing, then increase in size to form primary oocytes. Diploid primary oocytes divide by meiosis producing 1 large secondary oocyte and a small polar body. polar bodies are nonfunctional cells. Haploid secondary oocyte divides by meiosis producing 1 large ootid and a second polar body. Haploid ootid develops into a functional ovum.
Eggs are laid outside the body
oviparous
What are some characteristics of oviparous birth?
- Fertilization my be internal or external.
- Some animals abandon eggs while other provide extensive care.
Eggs are retained in the body
ovoviparous
What are some characteristics of ovoviparous birth?
- Essentially all nourishment is derived from the yolk.
- Common in some invertebrate groups and certain fishes and reptiles.
- Fertilization is internal
Give birth to young in a more advanced stage of development
viviparous
What are some characteristics of viviparous birth?
- Eggs develop in oviduct or uterus
- Embryos continuously derive nourishment from the mother
- Fertilization is internal
- Occurs in mammals and some fishes
- Provide more protection to offspring
Describe an acoelomate protostome.
Mesodermal cells completely fill the blasocoel. The gut is the only body cavity.
Describe a pseudocoelomate protostome.
Mesodermal cells line the outer edge of the bloastocoel. There is a gut cavity and a pseudocoelom, or flase body cavity that is only partially lined with mesoderm.
Describe a eucoelomate protostome.
Has a schizocoelous plan. Two cavities are formed, the gut cavity and the coelom, which is completely lined by mesoderm.
Process during embryonic cleavage by which molecules within the cytoplasm of each cell specify cell fate
cytoplasmic specification
The developmental response resulting from interactions with neighboring cells
Induction
Very little yolk distributed evenly in cytoplasm
Isolecithal eggs
Describe the cleavage that takes place in isolecithal eggs.
Cleavage is holoblastic and then either radial or spiral
Cleavage furrow extends completely through the egg; complete and approximately equal division of cells in an embryo
holoblastic cleavage
Cleavage planes are symmetrical to polar axis
radial cleavage
Cleavage planes are diagonal to the polar axis
Spiral cleavage
Moderate amount of yolk is concentrated at vegetal pole
Mesolecithal eggs
Describe the kind of cleavage that takes place in mesolecithal eggs.
Cleavage is holoblastic, but slowed in yolk-rich vegetal pole
Large amount of yolk concentrated at vegetal pole
Telolecithal eggs
Describe the cleavage that takes place in telolecithal eggs.
Cleavage is meroblastic because cleavage furrow can’t cut through heavy yolk. Therefore, cleavage is confined to a narrow disk on top of the yolk
Large amount of yolk is concentrated in the center
Centrolecithal eggs
Descrive the cleavage that takes place in centrolecithal eggs.
Cleavage is meroblastic and superficial.
Cleavage restricted to the cytoplasmic rim of the egg because furrow can’t cut through yolk at all
Superficial cleavage
Maintenance of an internal steady state by means of self regulation
homeostasis
Body temperature varies directly with environmental temperature
Poikilotherms
Maintain a relatively constant internal environment
Homeotherms
Rely mainly on external energy sources
Ectotherms
Rely heavily on metabolic energy
Endotherms
Dropping of body temperature when asleep or inactive
Daily torpor
What behavioral adjustments do ectotherms use to regulate body temperature?
They can burrow to stay warm at night and in the cool morning. They bask in the sun mid-morning and late afternoon. They retreat to shaded areas during the hottest part of the day
What metabolic adjustment do ectotherms have to regulate body temperature?
Most ectotherms can adjust metabolic rate to the prevailing temperature. Temperature compensation involves comples biochemical and cellular adjustments
How do endotherms maintain a constant body temperature?
Heat loss by radiation, conduction and convection, and by evaporation of water. Generate heat by exercise or shivering, decrease heat loss by increasing insulation, increasing caloric intake
Endotherms in hot environments
fossorial, nocturnal, glossy fur, insulation, fat distribution (isolated on back) temperature tolerance
living in the ground
fossorial
Endotherms in cold environments
decreased conductance and increased heat production
Countercurrent heat exchange
- well insulated body can lose substantial heat along exposed limbs
- arterial blood in the leg of an artic mammal or bird passes in contact with returning cold blood
- heat exchange along opposite vessel transfers body heat to returning venous blood that returns to the body core
- footpads must be able to operate at near freezing
summer dormancy in some invertebrates and vertebrates
estivation
Describe hibernation
- entry is gradual
- animal eventually cools to near ambient temp
- respiration and heart rates drops significantly
- arousal is slow an may involve shivering an nonshivering thermogenesis
a hormonally induced period of dormancy and developmental delay
diapause
eat drifting microscopic particles of plankton and organic debris
suspension feeders (filter feeders)
extraction of organic material or detritus from substrate
deposit feeding
croppers
- abundant food
- low quality food
- invest in ingestion and digestion
- most abundant forager type
active hunters
- less abundant food
- high quality food
- investment in foraging
- less common than cropper
sit and wait hunters
- least abundant food source
- high quality food
- low investment in ingestion, digestion, and foraging
- small quantities of food
- least common
endocytosis of food particles followed by digestion in food vacuoles
intracellular digestion
breakdown of food particles outside cells
extracellular digestion
