Exam 2 (Chapter 5, 6 and 7) Flashcards
(115 cards)
Biotic factor
Host cell density (affects infection rates), the presence of specific host species, and the activity of other microbes (e.g., bacteria that might degrade viral particles)
Abiotic factors
Temperature, salinity, UV radiation (can damage viral DNA), and the availability of nutrients
Viruses are important in controlling bacterial populations through
lysis (bursting) of cells, which releases nutrients and organic matter back into the environment. This process, known as the “viral shunt,” alters nutrient cycling and food web dynamics. They also play a role in horizontal gene transfer between bacteria.
Difference of prokaryotes
Lack a nucleus and other membrane-bound organelles. Their DNA is typically a single circular chromosome. They are generally smaller than eukaryotes. (e.g., Bacteria, Archaea)
Differences of eukaryotics
Possess a nucleus and other membrane-bound organelles like mitochondria and chloroplasts. Their DNA is organized into multiple linear chromosomes. (e.g., Protists, Fungi, Plants, Animals)
Chemosynthetic and photosynthetic bacteria similar
Both are autotrophs, meaning they produce their own food (organic compounds) from inorganic substances. They both form the base of food webs in certain ecosystems.
Chemosynthetic and photosynthetic bacteria difference
1) Energy Source
2) Habitat
How do marine bacteria contribute to the availability of nutrients in the ocean?
1) Decomposition
2) Nutrient Cycling
3) Dissolved Organic Matter (DOM) Consumption
Similarities of Archaea and true bacteria
Both are prokaryotic, single-celled organisms with no nucleus or membrane-bound organelles. They also share similar shapes and sizes.
Differences of Archaea and true bacteria
1) Cell Wall Composition
2) Membrane Lipids
3) Genetics
Why are archaeans sometimes called extremophiles?
Many archaea thrive in extreme environments such as high temperatures (thermophiles), high salinity (halophiles), high pressure (piezophiles), or extreme pH levels. Their unique adaptations allow them to survive where other organisms cannot
What is the ecological role of marine fungi?
1) Decomposers
2) Parasites
3) Symbionts
4) Carbon cycling
Centric Diatoms:
Radially symmetrical. Commonly planktonic.
Pennate Diatoms:
Bilaterally symmetrical. Can be planktonic or benthic
Why do some photosynthetic dinoflagellates kill fish (nutrient hypothesis)
The “nutrient hypothesis” suggests that excess nutrients (like nitrogen and phosphorus) in the water can lead to blooms of certain dinoflagellates. Some of these dinoflagellates produce toxins that can kill fish or create anoxic conditions that suffocate fish.
Why don’t the calcareous skeletons of forams and coccolithophores accumulate in the deepest parts of the ocean?
The calcium carbonate (CaCO3) that makes up their skeletons dissolves at great depths due to the increased pressure and lower temperatures. The depth at which CaCO3 dissolves is called the lysocline, and the depth at which the rate of dissolution increases dramatically is called the carbonate compensation depth (CCD).
Diatom and dinoflagellates’s critical role
1) Primary Producers
2) Oxygen Production
3) Carbon Cycling
Diatom and dinoflagellates’s harmful effects
1) Harmful Algal Blooms (HABs)
2) Fish Kills
What are the functions of long projections coming out of many marine microbial species?
1) Increased Surface Area
2) Buoyancy
3) Defense
4) Attachment
5) Movement
Rhodophyta (Red Algae)
1) Characteristics
2) Habitat
Phaeophyta (Brown Algae):
1) Characteristics
2) Habitat
Chlorophyta (Green Algae):
1) Characteristics
2) Habitat
Major body parts (eg. holdfast, stipe, thallus, blade, pneumatocyst
1) Holdfast
2) Stipe
3) Thallus
4) Blade
5) Pneumatocyst
Differences in pigment utilization for photosynthesis
- Different algae have different pigments that absorb different wavelengths of light. This allows them to live in different depths of the ocean where different wavelengths of light penetrate. 2. Green algae use primarily chlorophyll, brown algae use fucoxanthin in addition to chlorophyll, and red algae use phycoerythrin in addition to chlorophyll