NEX Science

autotrophs

plant cells have chloroplasts for photosynthesis and use this process to produce their own food

heterotrophs

animals that rely on other sources of food

cell membrane

made of up lipids and proteins. protects the cell but also allows communication with the outside enviroment

nucleus components

nuclear envelope, nucleoplasm, chromatin, nucleolus

nuclear envelope

acts as a barrier that separates the nucleus from the cytoplasm of a cell, protecting the cell's genetic material (DNA) by keeping it separate from the chemical reactions occurring in the rest of the cell, and regulating the movement of molecules between the nucleus and cytoplasm

Chromatin

consists of DNA and histones that are packaged into chromosomes during mitosis

nucleolus

dense central portion of the nucleus, produced and assembles ribosomes with the help of RNA and proteins.

Chloroplasts

organelles in plant and algae cells that convert sunlight into chemical energy

Thylakoids

chlorophyll molecules on their surfaces

Stromal lamellae

separate the thylakoid stacks

Mitrochondria

break down sugar molecules and produce energy in the form of molecules of adenosine triphosphate

ribosome

consists of RNA and proteins. they are protein factories that synthesize proteins by translating messenger RNA.

messenger RNA

used by the ribosome to generate a specific protein sequence

transfer RNA

collect the needed amino acids and delivers them to the ribosome

golgi apparatus

packs, ships, and distributes products (proteins/lipids) into shipping containers called vesticles.

cytoskeleton

organelles made up of proteins called microtubules. They provide shape, support, and the ability to move. Also help chromosomes during mitosis.

mitosis

one part ell divides into two identical daughter cellsthrough a series of steps including prophase, metaphase, anaphase, and telophase.

prophase

spindle fibers appear and the DNA is condensed and packaged as chromosomes that become visible. Nuclear membrane breaks down and nucleolus disappears.

metaphase

spindle apparatus is formed and the centromeres of the chromosomes line up.

anaphase

centromeres divide and the two chromatids separate and are pulled towards opposite ends of the cell

telophase

spindle fibers disappear, nuclear membrane reforms, and DNA in chromatids is decondensed.

cytokinesis

diving the cytoplasm and cell membrane by the pinching of a cell into two new daughter cells.

meiosis

cell division in which the number of chromosomes is reduced by half.

meiosis I

cell replicates its DNA in interphase and then continues through prophase, metaphase, anaphase, and telophase.

meiosis II

cell enters a brief interphase but does not replicate its DNA. then the cell continues its cycle. At the end there are four daughter cells and half the number of chromosomes as the parent cell.

missense mutation

result in a codon for a different amino acid

silent mutation

result in a codon for the same amino acid as the original sequence.

nonsense mutation

a premature stop codon, resulting in a non-functional protein.

somatic mutations

develop after conception and occur in an organism’s body cells such as liver cells, or brain cells.

germline mutations

occur in an organism’s germ cells, which are only egg and sperm cells. It may be passed on from parent to offspring

law of segregation

alleles separate when gametes are formed. only one pair of alleles for a given trait is passed to the gamete.

monohybrid cross

genetic cross between two organisms with different variation for a single trait.

homozygous

having two identical copies of a gene, one inherited from each parent (gg)

heterozygous

a separate allele for a particular trait (Gg)

dominant

The allele that is expressed more (GG)

genotype

genes that may not be expressed (like recessive genes)

phenotype

physical, visual genes. (ex. eye color)

dihybrid cross

two traits that each have two alleles

genetic drift

process that causes random changes in allele frequencies that are not result of natural selection. can result in loss of genetic diversity.

genetic bottleneck

occurs when there is a drastic reduction in population due to some change. Such as overhunting, disease.

founder effect

when one individual populate a new area.gene

gene flow

alleles enter a population by immigration and leave a population. helps counter genetic drift.

natural selection

the process through which populations of living organisms adapt and change. “survival of the fittest”

artificial selection

the process of humans choosing organisms with specific traits to reproduce, resulting in new types of organisms. For example, cabbage and broccoli.

homology

similarity of structures of different species based on a similar anatomy in a common evolutionary ancestor.

endosymbiosis

the development of the organelles of mitochondria in animals and chloroplasts in plants.

viruses

non living, infectious particles that act as parasites in living organisms. they cannot reproduce outside of living cells.

the structure: nucleic acid genome (DNA or RNA) surrounded by a protective protein coat or capsid.

capsid

may be surrounded by a lipid membrane or envelope

bacteria

small, prokaryotic, single celled organisms

capsule in bacteria

enhances their ability to cause disease. they can be heterotrophs or autotrophs.

protists

small, eukaryotic single celled organisms. There are three forms, plantlike protists, animallike protists, and fungus like protists.

plant like protists

algae that contain chlorophyll and perform photosynthesis.

animal like protists

protozoa with no cell walls that lack chlorophyll and are grouped by their method of locomotion, why way use flagella, cilia.

fungus like protists

do not have chitin in their cell walls, and are generally grouped together as slime mods or water molds.

fungi

nonmotile organisms with eukaryotic cells and contain chitin in their cell walls.

hyphae

fungi have it and they are grouped together into mycelium. they include mushrooms and toadstools.

vascular plants

have leaves, stems, and roots that contain xylem and phloem

nonvascular plants

lack true leaves, stems and roots and do not have any true vascular tissue. But instead they rely on diffusion and osmosis to transport materials needed to survive.

bilateral symmetry

the organism cut in half along one plane to produce two identical halves. (ex. mammals, birds, fish)

radical symmetry

cut in half along several planes to produce two identical halves. (ex. starfish, jellyfish)

asymmetry

organism exhibits symmetry.

sexual reproduction

males and females have different reproductive organs called gametes

gametes

males have testes that produce sperms, and females have ovaries that produce eggs

zygote

when the spern cell unites with the egg cell

oviparous

mammals that lay eggs

viviparous

mammals that have a uterus in which the embryo develops

organizational hierarchy

cells, tissues, organs, organ system, orgainism

tissues categories

muscle tissue, connective tissue, nerve tissue, epithelial tissue

muscle tissue

composed of skeletal muscle cells, cardiac muscle cells, or smooth muscle cells

skeletal muscle cells

muscles called biceps, triceps, hamstrings and quadriceps

cardiac muscle cells

only found in the heart

smooth muscle cells

provides tension in the blood vessels, controls pupil dilation, and aids in peristalsis

connective tissues

include bone tissue, cartilage, tendons, ligaments, fat, blood, lymth

nerve tissue

located in the brain, spinal cord, and nerves

epithelial tissue

the layers of skin and various membranes

hypothalamus

the central portion of the brain linked to the endocrine system through the pituitary gland. it releases special hormones that influence secretion of pituitary hormones. (controls body temperature, hunger, thirst, sleep, behaviors, etc)

endocrine system

consists of glands that produce hormones to help coordinate functions of the body.

Antidiuretic hormone (ADH)

helps maintain homeostasis in vertebrates. produced by the posterior pituitary gland and regulates the reabsorption of water in the kidneys and concentrates the urine.

Pancreatic islets

located in the pancreas. insulin and glucagon work together to maintain the blood glucose level

insulin

stimulates cells to remove glucose from the blood

Glucagon

stimulates the liver to convert glycogen to glucose

angiosperms

flowering plants. they reproduce seeds that are enclosed in an ovary, like a fruit. (flowers, vegetables)

gymnosperms

non-flowering plants. they reproduce by unenclosed seeds on scales, leaves, or cones. (pines, spruces)

stomata

epidermis

plant dermal tissue. a single layer of closely packed cells that covers leaves and young stems

guard cells in epidermis

controls the opening and closing of the stomata. they do not have chloroplasts.

periderm

cork cells or phellem, phelloderm. Cork is the outer layer of the periderm of nonliving cells. it is to protect and provide insulation for the plant

phloem

transports dissolved sugars produced during photosynthesis to non-photosynthesis areas of the plant (active transport)

ground tissue types

parenchyma tissue, collenchyma tissue, and sclerenchyma tissue

parenchyma tissue

is food storage, and tissue repair. (mesophyll)

collenchyma

provides support of roots, stems, and petioles

sclerenchyma

provides rigid support and protection. may contain cellulose or lignin

pedicel

stalk with a receptacle or enlarged upper portion which holds the developing seeds

sepals

leaf like structurethat protects the bud

petals

help attract pollinators

stamen

consists of the anther and filament

anther

where pollen is produced

pistil

consists of the stigma, style and ovary. the ovary contains the ovules which house the egg cells.

osmosis

the process by which water molecules pass through a semipermeable membrane from an area of high water concentration to an area of low water concentration

active transport

a process that involves the movement of molecules from a region of lower concentration to a region of higher concentration against a gradient or an obstacle with the use of external energy

starch

what plants use to store glucose