science notes 3rd quarter

note: i may have made a few mistakes so pls don't solely rely on this!!! check ur book and own notes as well to be sure ^^

central dogma of molecular biology

is a fundamental principle that explains the flow of genetic information in living organisms. it states that genetic information flows from dna to rna to proteins, but not the reverse.

central dogma of molecular biology

this principle was first proposed by francis crick in 1958 and has since been a fundamental concept in the field of molecular biology.

dna (deoxyribonucleic acid)

hereditary material in humans and organisms, carrier of genetic information

rna (ribonucleic acid)

is a polymeric molecule that is essential for most biological functions, either by performing the function itself or by forming a template for the production of proteins

components of dna

adenine, guanine, cytosine, thymine

components of rna

adenine, cytosine, guanine, uracil

dna replication

process of copying double-stranded dna molecules

semi-conservative replication

origin of replication; replication fork

pyrimidines

single = 1 ring

purines

double = 2 rings

chargaff’s rule of pairing

adenine - thymine (2 hydrogen bonds) | guanine - cytosine (3 hydrogen bonds)

enzymes (-ase)

they make the process of dna replication easier and faster

1st step of dna replication

‘unzip’ the double helix structure

helicase

essential during dna replication because they separate double-stranded DNA into single strands

2nd step of dna replication

separation of two single strands will form into a replication fork

leading strand

3’-5’ direction

lagging strand

5’-3’ direction

rna primase

makes the primer which acts as the starting point for dna synthesis. functions by synthesizing short RNA sequences that are complementary to a single-stranded piece of DNA

dna polymerase

adds new complementary nucleotide bases towards the replication fork. it completes the dna sequence. are enzymes that create DNA molecules by assembling nucleotides

okazaki fragments

rna primase given by lagging strand

exonuclease

strips away the primer(s), proofreads and serves as an editor, also removes primer

dna ligase

seals up the sequence of dna into 2 continuous double strands (serves as a glue), also fills in the gap of the removed primer

semi-conservative strand

1 old strand, 1 new strand

location of dna replication in plants and organisms

cytoplasm of prokaryotes

location of dna replication in humans

nucleus of eukaryotes

protein synthesis

process of creating protein

2 main process of protein synthesis

transcription and translation

transcription

template of dna the rna is copying from

translation

rna goes to ribosome (cell organelle) to be translated into protein

codon

sequence of three nucleotides in dna or rna that encodes information in creating amino acids or protein

natural selection

a theory proposed by charles darwin and the process through which populations of living organisms adapt and change.

biodiversity

different species, habitats, organisms

carolus linneaus

father of taxonomy, classified animal names and organisms, implemented the terms genus and species and created their scientific names

george louis leclerc de buffon

proposed the theory that organisms shared ancestors but are unrelated to each other

erasmus darwin

proposed the theory that all living things were descended from a common ancestor

jean-baptiste lamarck

proposed the theory that all organisms evolved toward perfection and complexity

charles darwin

proposed the theory of natural selection and that it is a survival of the fittest and adaptability is what makes organisms survive

galapagos island

a very sensitive island that preserves wildlife and only a few can visit this island

variation

heritable differences among single species resulting from differences in genetic traits

overproduction

increase in reproduction, greater chance to survive

adaptation

cope with the fast-changing type of environment

descent for modification

present-day organisms are descendants of ancestral species, many individuals possess the traits

evidence

can be classified as fossil, embryological, anatomical

fossil evidence

fossils are preserved remains of an organisms. most common fossils are bones, shells, seeds, teeth, and pollen grains.

embryological evidence

embryology; study of embryos and their development. embryonic development are further evidence that living things evolved

anatomical evidence

comparing the body structures of living species also provide clues pointing to evolution and the common ancestry of organisms

homologus structure

physical structures of the organisms that have the same evolutionary origin and position yet have different functions

vestigial structure

structure of animals that is gradually disappearing; inherited body parts which are smaller and often unused

analogus structure

have similar functions but have a different anatomy

genetics

basic heredity for all of life

fossils

remnant, impression, or trace of an animal or plant of a past geologic age that has been preserved in earth’s crust.

water, temperature, light, atmospheric pressure, chemical components

factors affecting survival

water and atmospheric pressure (air)

organisms need this to survive

temperature

helps maintain the ideal homeostasis

light

main source of energy; plants use this for photosynthesis

chemical compounds

derived mostly in plants and other food sources

balance of nature, diversity and stability, finiteness of resources, stewardship

core principles to attain biodiversity and stability

balance of nature

can only support a given number of individuals at a time

diversity and stability

more diverse ecosystems, more resilient and stable

finiteness of resources

limitation on the most common resources

stewardship

act of protecting, conserving, and preserving our nature

population density, spatial distribution patterns, population range, reproduction patterns

population characteristics

population density

number of individuals over a unit area

spatial distribution patterns

capability to spread and occupy a specific area

uniform, random, and clumped dispersion

types of dispersion

uniform dispersion

a dispersion in which there are equal spaces in between organisms

random dispersion

a dispersion in which there are no equal or have random spaces between organisms

clumped dispersion

a dispersion in which organisms’ group and stay together

population range

how organisms are distributed

reproduction patterns

expanding, stable, declining

density-independent factor, density-dependent factor

limiting factors

density-dependent factor

biotic factor—interactions, competition for food, water, space, parasites, and diseases. population matters

density-independent factor

abiotic factor—atmospehric conditions, human-intervention. population doesn’t matter

birth rate, death rate, immigration, emigration

population variables

formula for population change

(birth + immigration) - (death + emigration) if answer is positive, increase. if answer is negative, decrease.

exponential growth

constantly increasing, unlimited resources and no diseases at all, population size will increase, an ideal concept for organisms. (j - shape)

r-strategists

bacterias, yeast, fungi - can reproduce more

logistic growth

type of growth that exhibits a steady expansion followed by an abrupt slowdown. influenced by the limited resources in the environment known as the carrying capacity (s-shape)

resilience and resistance

these two values will equate to stability and an ideal ecosystem

logistic growth phases

(1) unlimited supply; will experience exponential growth, favorable time for population to increase (2) increase in population (3) no decline, constant increase in population (4) overpopulation will lead to scarcity, do not exceed carrying capacity or else it will lead to competition - death - and extinction

seminal vesicles

these are sac-like pouches that attach to the vas deferens near the base of the bladder. It can produce a sugar-rich fluid (fructose) that provides sperm with a source of energy and helps with the sperms' motility. (ability to move).

vulva

the female external reproductive organs consist of the mons pubic, which is covered with pubic hair; two folds of tissue, called the labia majora and labia minora, which surround a space called vestibule.

mons Pubis

it is formed at the upper margin of the symphysis pubis and is shaped like an inverted triangle. It is located over the two pubic bones of the pelvic. This structure is composed of fatty tissue lying beneath the skin and from puberty on, is covered with varying amount of hair.

labia Majora

are two folds of fatty tissue that form the lateral boundaries of the vulva. they are covered with coarse skin and pubic hair on the outer aspect and are smooth and moist on the inner aspect, where the openings of numerous small glands are found.

labia Minora

are soft folds of skin that are rich in sebaceous glands. it is moist and composed of erectile tissue containing loose connective tissue, blood vessels, and involuntary muscles. Its functions are to lubricant and waterproof the vulvar skin and to provide bactericidal secretion that help prevent infections.

clitoris

it is a small, sensitive structure that, like the penis, is composed of erectile tissue, nerves, and blood vessels; it is covered at the tip with very sensitive tissue. It exists primarily for female sexual enjoyment.

vaginal vestibule

it is a boat shaped depression enclosed by the labia minora and is visible when the labia minora are separated. it contains the introitus.

urethra

this is just below the clitoris. although it is not related to sex or reproduction, it is included in the vulva and is actually used for the passage of urine. connected to the bladder.

hymen

it is a thin, elastic, mucous membrane that partially covers the vagina in young females. does not seem to have a specific physiological function or purpose. many shapes are possible.

perineum

it is the short stretch of skin starting at the bottom of the vulva and extending to the anus. It is a diamond shaped area between the symphysis pubis and the coccyx. this area forms the floor of the pelvis and contains the external sex organs and the anal opening. it may tear during the birth of an infant.

vagina

it is a curved tube leading from the uterus to the external opening at the vestibule. it lies between the urinary bladder and the rectum. it consists of muscle and connective tissue and is lined with epithelial tissue, which contains folds called rugae.

purposes of a vagina

it receives the penis and semen of a male. the pathway of the baby during childbirth. provides the route of menses from the uterus to leave the body. may hold the diaphragm and female condom.

cervix

it consists of a cervical canal with an internal opening near the uterine corpus called the internal os and an opening in to the vagina.

purposes of a cervix

providing lubrication for the vagina. acting as bacteriostatic agent. providing an alkaline environment to shelter the sperm from the acidic vagina. producing a mucous plug in the cervical canal during pregnancy.

uterus

it is a womb, is a hollow, pear-shaped, muscular organ. It is supported by two important pairs of ligaments, the round and broad ligaments. this is divided into three portions and parts: fundus (upper portion), the corpus (body), the cervix. It also has three layers: (perimetrium, myometrium, endometrium).

purposes of a uterus

for menstruation, pregnancy, labor and birth

fallopian tube

it can extend laterally from the uterus, one to each ovary. they are small, narrow tubes. the tubes carry the ovum from the ovary to the uterus by the contraction of the cilia: hair like projections found in the lining of the tubes. Extending from the ends of these tubes are small, fingerlike projection called fimbriae.

purposes of the fallopian tube

a passageway in which sperm meets the ovum. a site of fertilization. a safe nourishing environment for the ovum or zygote. a means of transport of the ovum or zygotes to the corpus of the uterus.

ovaries

these are two small, almond shaped organs located on each gland. they are responsible for producing the female sex hormones: progesterone and estrogen. also responsible for the development and maturation of the ovum.

breasts

it is composed of glandular, ductal, connective, and adipose tissue. embedded in the fibrous tissue are fat and lobules which make up the mammary glands, accessories to reproduction in women, but rudimentary and functionless in men.