midterm Flashcards
the 7 characteristics of life
display order, harness and utilize energy, reproduce, respond to stimuli, exhibit homeostasis, grow and develop, evolve
scientific method consists of what
- hypothesis 2. experiments and observations 3. analyzing the data 4. conclude- support or reject
how can substances penetrate the cell membrane?
through transport protein channels
what is the plasma membrane made of?
a bilayer of lipids(hydrophobic) embedded with protein molecules
what are the common shapes of prokaryotic cells?
cocci, bacilli, spirilla, square cells
what are the structural features of bacteria and archaea (prokaryotes)?
cell wall, DNA, ribosomes, flagella, pili
what does the plasma membrane do in prokaryotes?
metabolize food molecules in chemical energy (ATP)
what is the plasma membranes rigid external cell wall called?
glycocalyx— capsule
what does the flagella do?
how bacteria and archaea move, pushes cell through liquid medium
what are the pili made of and what do they do?
made of protein and attach bacterial cells to other cells as part of infection
what are plasmids and what do they do?
small circles of DNA, they replicate independently and provide bacteria with genetic advantages ex. antibiotic resistance
what are prokaryotic chromosomes?
single, circular DNA packaged into nucleoid
what are the 4 eukarya groups?
protists, fungi, plants, animals
what does the plasma membrane do in eukaryotic cells?
channel proteins for transport, receptors to bind molecules and trigger internal responses
what is a misconception about fungi?
that they are closely related to plants- they are more like animals
what are fungi?
heterotrophic eukaryotes that obtain carbon by breaking down organic molecules synthesized by other organisms
what are chloroplasts?
yellow-green plastids where photosynthesis takes place in plant cells
what are thylakoid membranes?
contain chlorophyll, a green pigment that absorbs light energy and converts it to chemical energy in photosynthesis
what are central vacuoles and what do they do?
large vesicles that store salts, organic acids, sugars, storage proteins, pigments, and sometimes waste products. they also contain enzymes that break down molecules and have molecules that provide chemical defences
what are cell walls made of and what do they do in plant cells?
made of cellulose fibres that provide tensile strength. they support cells, contain pressure from vacuole and protect cells from bacteria and fungi
what are photoautotrophs?
use light from the sun (energy) and inorganic materials (CO2 and H2O) for photosynthesis
what are chemoautotrophs?
use inorganic compounds (H gas, S, NH3, nitrites, Fe) as energy sources for chemosynthesis
what are heterotrophs?
use energy in organic matter obtained from other organisms
what are photoheterotrophs?
use light from sun to generate ATP but need to take in organic compounds from their environment like alcohol or fatty acids ex. halobacterium
what are chemoheterotrophs?
must obtain organic compounds for both energy and as a carbon source ex. bacteria
what is photosynthesis?
the use of light energy to convert CO2 into an organic form
which photosynthetic organisms are the primary producers of earth?
photoautotrophs
which domains are photosynthesis present in?
bacteria and eukarya NOT archaea
what are autotrophs?
organisms that make required organic molecules from inorganic sources (CO2 and water)
what are photoautotrophs?
autotrophs that use light as the energy source to make organic molecules by photosynthesis ex. bacteria, protists, and plants
what are chemoautotrophs?
autotrophs that use compounds such as hydrogen sulfide and ferrus irons as a source of energy ex. bacteria and archaea, NO eukaryotes
why are all animals heterotrophs?
they obtain carbon from organic molecules, living hosts, wastes, or remains of dead organisms
what is metabolism?
the collection of all chemical reactions present within a cell or organism
what is an anabolic pathway?
a series of reactions that results in the synthesis of larger and more complex molecules from simpler molecules ex. biosynthesis of carbs, proteins, and nucleic acids
what is a catabolic pathway?
a series of chemical reactions that results in the breakdown of larger, more complex molecules into smaller less complex one ex. cellular respiration - energy rich food molecules are converted into simpler and lower energy molecules
how are catabolic and anabolic pathways linked?
through chemical energy (ATP, NADH, NADPH)
what’s an ATP?
specific form of chemical energy that links the catabolic and anabolic pathways
what is ATP hydrolysis?
provides free energy and can be used as a source of energy for the cell as a result of its reaction with water
what are the advantages and disadvantages of asexual reproduction?
large number of offspring produced quickly, only 1 individual required… no genetic variation
what are the advantages and disadvantages of sexual reproduction?
increase genetic variation, enhance reproductive success in changing environments… locate a mate
what are the types of asexual reproduction involving mitosis?
fission, budding, and fragmentation
what is parthenogenesis?
asexual reproduction where females produce eggs that develop without being fertilized
how does the amoeba reproduce?
extends its pseudopodia where the cytoplasm and nucleus flow into, multiple fission in unfavourable conditions and binary fission in favourable conditions
what creatures use parthenogenesis to reproduce?
fish, reptiles, scorpions, mites, bees, never in mammals
what is apomixis?
asexual reproduction in plants without egg fertilization ex. dandelions
what is a hermaphrodite?
a sexually reproducing organism that produces both male and female gametes
what is conjugation?
2 organisms fuse along a common surface (bridge/connection) and exchange genetic material, no increase in number of individuals ex. paramecium, spirogyra
how do daphnia reproduce?
cyclic reproduction, alternate between sexual and asexual reproduction