Unit 1 Flashcards
what does CHARRGED stand for
Cell, Homeostasis, Adapts, Responds, Reproduces, Grows, Energy, DNA
what are the 8 processes IB wants you to know
Metabolism, Response to Stimuli, Homeostasis, Movement, Growth, Reproduction, Excretion, Nutrition
what is biology
bio- life // ology- the study of
Charrged (cells)
living things are made up of one or more cells // organisms can be unicellular (made of one cell) or multicellular (made of more than one cell)
chArrged (adapt/evolve)
over generations, groups of living things change over time (because their genetic information changes). this is known as adaptation and evolution
cHarrged (homeostasis)
the ability to maintain a constant internal environment is called maintaining homeostasis
chaRrged (response)
organisms notice and react to stimuli from their environment // reacting to stimuli (changes in the environment) can often lead to movement
charRged (reproduce)
all living things make new, similar, living things
charrGed (grow)
every organism has a pattern of growth and development
charrgEd (energy)
all living things must take in materials & energy // many chemical reactions occur within living things in order to build up and break down materials to facilitate these processes. all of these chemical reactions together are known as “metabolism”
charrgeD (DNA)
all living things store the information they need to live, grow, and reproduce in a genetic code written in a molecule called DNA
3 things about cell theory
- all living things are made of one or more cells
- cells are the basic unit of life
- cells come from pre-existing cells
3 things about the conditions on early earth
- early earths atmosphere lacked free oxygen & ozone and had an abundance of CO2 and CH4 (carbon dioxide & methane)
- without ozone, there was more UV light that reached the surface of the earth
- CO2 & CH4 are greenhouse gases - gases that trap heat - increasing the temperature of early earth
miller and urey’s experiment
created an experiment to stimulate the conditions on prebiotic earth they investigated what types of molecules could form in the conditions of early earth (combined H2O, CH4, NH3, and H2 with heat and electricity: under these conditions, several simple organic molecules, including amino acids were found)
formation of the first cells
- the first cells (proto cells) had to have formed spontaneously and in an aqueous environment
- self-replication of molecules and self-assembly of cells were necessary for the evolution of the first cells
- protocells must have been significantly less complex than current cells
spontaneous formation of vesicles
- when in an aqueous environment, fatty acids will spontaneously self-assemble to form spherical bilayers
- the spherical bilayer forms a membrane that separates the internal environment from the external environment
what does RNA stand for
ribonucleic acid
what is RNA thought to be
RNA is thought to have been the first genetic material - not only can RNA act as genetic material, but it also has catalytic properties
what does LUCA stand for
Last Universal Common Ancestor
what is the evidence for LUCA
- universal genetic code
- conserved genes across all organisms
what was LUCA likely to be
a unicellular, autotrophic, microbe that existed between 2.5 and 3.5 billion years ago
LUCA and hydrothermal vents
- fossilized evidence suggests that LUCA could have evolved around the hydrothermal vents
- hydrothermal vents remain a hotbed of life even today
- organisms thrive in the mineral rich environment surrounding the vents
COMPARISONS of prokaryotic and eukaryotic cell structure
- have DNA
- have a cell membrane
CONTRASTS of prokaryotic and eukaryotic cell structure
- prokaryotic cells have flagellas whereas eukaryotic cells do not
- eukaryotic cells have a nucleus whereas prokaryotic cells have a nucleoid
what kind of cells have ribosomes
all of them
what is the difference between eukaryotic and prokaryotic ribosomes
prokaryotic cells: 70s // eukaryotic cells: 80s
eukaryotes include…
plants, animals, fungi, protists
inside of an animal cell
- a place where the cells activities are controlled
- a place where chemical reactions happen
- a place where substances can pass in and out of the cell
- a place where energy is release for the cell
inside of a plant cell
- same features as animal cells
- a place where light is captured for photosynthesis
- a place where water & other materials are stored
- a place to help support and strengthen the cell
both type of cells have these:
mitochondria, ribosomes, nucleus, cell membrane, cytoplasm
only plant cells have these
central vacuole, chloroplasts, cell wall
what is a flagella
lash-like appendage that protrudes from the cell body
what is a cilia
slender protuberances that project from the much larger cell body
atypical cell structure in eukaryotes
numbers of nuclei illustrate one type of atypical cell structure in aseptate fungal hyphae, skeletal muscle, red blood cells, and phloem sieve tube elements
aseptate fungal hyphae
- challenges the idea that a cell is a single unit
- fungal hyphae are very large, forming a tubular system with many nuclei and a continuous cytoplasm
- like muscle cells they are multi-nucleated
- they have cell walls composed of chitin
- the cytoplasm is continuous along the hyphae with no end cell wall or membrane
striated skeletal muscle
- challenges the idea that a cell has one nucleus
- muscle cells have more than one nucleus per cell
- muscle cells called fibres can be very long (300 mm)
- they are surrounded by a single plasma membrane but they are multi-nucleated (many nuclei)
- this does not conform to the standard view of a small single nuclei within a cell
red blood cells
- red blood cells have no nucleus when they are mature to allow for more hemoglobin storage
- red blood cells have no DNA and thus cannot replicate bone marrow must continually produce new RBC’s
- the atypical structure of RBC’s challenges the cell theory
phloem sieve tubes in plants
- sieve elements line the phloem in plants and are interconnected into tube assemblies that transverse the length of a plant
- these sieve tubes lack nuclei and have few organelles, relying on local companion cells for survival
- phloem sieve tubes challenge the idea that multicellular structures are composed of independent cells
endosymbiotic theory
- lynn margulis (1964)
- “eukaryotic cells evolved from prokaryotic cells”
- major organelles in eukaryotic cells are thought to have once been prokaryotic cells that established symbiotic relationships
- mitochondria & chloroplasts
evidence supporting endosymblosis
- mitochondria and chloroplasts have a double membrane
- mitochondria and chloroplasts have their own ribosomes
- mitochondria and chloroplasts have circular DNA
- mitochondria and chloroplasts reproduce independently of the rest of the cell and in a way that is similar to binary fission