cell division/embryology/energy Flashcards
interphase
when cell isn’t dividing Gap 1 = cell growth S = DNA Doubles centrioles double Gap 2= cell growth and prep for division longest stage of cell cycle
checkpoints
- internal and external signals provide stop and go signals at checkpoints
- cyclins and cyclin dependant kinases control the cycle
checkpoint failure?
often causes mutations and genomic arrangements resulting in genetic instability
birth defects + cancer
cell cycle
- mitotic phase and interphase alternate
- highly regulated
- checkpoints determine fate of the cell
diploid cells
2 sets of each chromosome- 1 from each parent
haploid cells
1/2 chromosomes 23
prophase
1st phase- condensation of chromosomes, disappearance of nucleolus, chromatids condense (chromosome x’s), microtubules are made for structure
metaphase
2nd phase- chomosomes attach to microtubules. start to be pulled towards edges, chromosomes line up in a line in the middle of the cell
anaphase
chromosomes separate, egg shape, ana=back
telophase
crease forms between cells, chromosomes go back to chromatin
cleavage
fission between 2 new cells before they break, done by cytokinesis
mitosis
- decision of nucleus of 2 diploid, (2n) somatic cells
- asexual reproduction, growth, repair
binary fission
cell division of prokaryotes
- DNA doubles
- cell elongates
- cell splits in half
G (sub 0)
takes place after G1
- cells get stuck and never return to cell cycle
- cells of the central nervous system
cytokinesis
divides the cytoplasm of the daughter cells equally
in plant cells- cell plate
in animal cells- cleavage furrow
meiosis
- makes sexual reproduction possible
- Haploid (n) gametes are produced from germ cells
- nuclear division of gametes
zygote
1st cell formed after fertilization
what triggers a cell to divide?
- size
- demand
- DNA signal
- cancer/damaged DNA
what stops cell division?
- dna signal
- cell touching borders
- death
- demand changes
- gametes
hayflick limit
number of times a cell can divide before it dies
~50
telomeres get shower with each cell division, when telomeres are gone, cell dies
ends seem to unravel
why we age and die
telomere
compound structure at the end of a chromosome
homologous chromosome
- 2 of each chromosome exists in each cell, except gametes
- they are identical in the types/locations of genes
- 1 set is from dad and one from mom
- orientation during meiosis is random, ensuring a nice mix of each
fertilization
- fusion of gametes
- increases variation
- restores diploid number
meiosis I
(1st of 2 rounds)
- crossing over, mix up DNA
- chromosomes reduced to 23 duplicated chromosomes
meiosis II
turns 23 duplicated chromosomes into 23 unduplicated chromosomes
telomerase
- prevents unraveling and can lengthen telomere
- some cancer cells produce it
- HeLa cells from Henrietta Lax- good for research bc they’re immortal
stages of development
egg & sperm-> fertilization -> cleavage -> gastrulation -> organogenesis -> metamorphosis
cleavage
division of zygote into smaller cells every 12-24 hours
morula
solid ball of cells
blastula
hollow ball of cells
gastrulation
- the movement of cells to create germ layers
- starts at dorsal lip
- results in gastrula
deuterstomes
anus is made first
protostomes
mouth is made first
3 germ layers
ectoderm (skin, nervous system, teeth, eyes)
mesoderm (blood, skeletal, muscular, circulatory, and lymphatic system)
endoderm (the tube- lining of respiratory, excretory, reproductive and digestive sys)
noggin and chordin (signals examples)
induce mesoderm to change to muscle and notochord (spine)
homeotic selector genes
genes whose expression affects the overall body plans/sequences
ex) bithorax/antennapedia
organogenesis
- organ formation begins
- apoptosis and gene activation/silencing are v important
apoptosis
“cell suicice”- hollows out blood vessels, creates fingers and toes, necessary for proper brain development and more
complete metamorphosis
-egg
-larva
-pupa
-adult
(butterflies, mosquito , beetles, frogs)
aging
depends on genes and environment
as we age our cells are less likely to divide and more likely to die
cellular respiration
extracting the energy from sugars and other fuels and storing them in the bonds of ATP
uses of ATP
a ton! same examples are transport, metabolism, bioluminesce
metabolism
- all of an organisms chemical reactions
- very responsive to subtle changes (enzymes regulate)
- tends to follow in a metabolic pathway
anabolism + catabolism =
metabolism
correlation between metabolic rate and unit body mass
inverse relationship- bigger animals have a slower metabolic rate and tend to live longer
kinetic energy
associated with the relative motion of objects, moving objects can perform work by imparting motion to other matter
-can also show up as heat or light
heat/thermal energy
- kinetic energy associated w the random movement of atoms or molecules
- exergonic relations vice endotherms their body temp
ectotherms
rely on environment for body temp
endotherms
warm blooded, exergonic reactions
potential energy
an object not in motion that has energy bc of its location or structure, can also be chemical
chemical energy
- PE stored in bonds, ready for chemical release
- ATP!!
thermodynamics
study of energy transformations or the effects of work, heat, and energy on a system
1st Law of Thermodynamics
- energy can be transferred or transformed, but it cannot be created or destroyed
- energy flows
- known as the principal of conservation of energy
what happens to energy after it has performed work?
- some lost as heat, into surroundings
- heat doesn’t really help organisms except for body temp
trophic level
energy chain level
entropy
measure of disorder or randomness
-losing energy makes world more disordered
2nd law of thermodynamics
- energy transfer or transformation increases entropy of the universe
- there’s an unstoppable trend towards randomization of biological systems and the universe as a whole
spontaneous processes
- a process that occurs without the input of energy
- energetically favorable, not necessarily quick
- increases entropy
free energy
energy available to do work
- excess free energy results in storage or growth
- insufficient results in loss of mass and ultimately death
sources of free energy
- photosynthetic orgs: the sun
- chemosynthetic orgs: small inorganic molecules
- heterotrophs: metabolize lipids, carbs, and proteins
Gibbs Free Energy
🔺G=🔺H- T 🔺S
🔺G= free or available energy in a system 🔺H= enthalpy or total energy in a system, usually hear 🔺S= entropy or disorder of a system T= temp in Kelvin
Decrease 🔺H
decrease 🔺G
Increase T
decrease 🔺G
Increase 🔺S
decrease 🔺G
negative change in free energy (- 🔺G)
spontaneous, exergonic, increase enthalpy
increase in free energy, (+ 🔺G)
non-spontaneous, endergonic, decreases enthalpy
photosynthesis energy
-endergonic, decreases entropy, +🔺G, activation E = the sun
cell respiration energy
exergonic, increases entropy, -🔺G
bioenergetic
overall flow of energy in an animal
-determines nutritional needs, and is related to the animals size, activity, and environment
basal metabolic rate
minimum metabolic rate for basic functions such as maintenance, heart beat, respiration, etc
relationship between overall metabolic rate and body bass
constant and linear
G1
cell grows and prepares to duplicate its DNA
S phase (Synthesis)
chromosomes are duplicated
G2
2nd growth phase, cell prepared to divide, replication is checked for integrity, errors are corrected, repairs are made
cyclin dependent kinases (CDKs)
enzymes that that turn on or off various processes that take place in cell division, partners with cyclins
primary productivity
the rate at which plants and other photosynthetic organisms produce organic compounds in an ecosystem
-2 aspects: gross productivity and net productivity
gross productivity
the entire photosynthetic production of organic compounds in an ecosystem
net productivity
organic materials that remain after photosynthetic organisms in the ecosystem have used some of these compounds for their cellular energy needs (cellular respiration)
