Biology - Vocabulary

Ligand

A small molecule that binds to a receptor that is used in cell communication.

Signal Transduction

the process where a signal received by the cell travels to the response area.

Lipid Ligand

a nonpolar ligand that is able to pass through a cell’s membrane.

Polar Ligand

usually proteins, and they cannot pass through membrane.

secondary messengers

molecules that take the signal received by the cell to the target area.

Phosphorylation Cascade

method of signal transduction where phosphate groups (from ATP) are de/attached to proteins, catalyzed by enzymes

Protein Kinase

a type of enzymes that helps attach phosphate to proteins during phosphorylation.

Protein Phosphatase

A type of enzymes that help remove phosphate from proteins during phosphorylation.

Cell Junctions

cells have structures that let them bind to adjacent cells

Cell Recognition

cells have special proteins that let other cells recognize them

Paracrine signaling

cell releases molecules to communicate w/ other cells in the neighborhood

Synaptic signaling

signaling between 2 neurons

Endocrine signaling

Cells signals are carried by the circulatory system to farther areas.

Haploid cell

a cell that has only one complete set of chromosomes

Diploid Cell

a cell that has two sets of chromosomes

Interphase

Cell’s growth development phase before mitosis and cytokinesis. G_1, S, G₂

G₁

Where the cell replicates all the organelles and grows

G₀

when cell is dormant, not gonna reproduce yet

S phase

DNA replication

G₂

cell checks for DNA damage and prepares for mitosis

cyclin

a protein used in cell cycle check points that activates cyclin-dependent kinases

cyclin dependent kinases

enzymes that phosphorylate other proteins to continue the cell cycle

Mitosis

process of splitting the nucleus

prophase

DNA coils into chromosomes and mitotic spindle starts to form and nuclear membrane breaks down

Metaphase

chromosomes line up in the equator and spindle fibers attach

centromere

snatched waist of the chromosome

Kinetochore

a protein on the centromere that lets spindle fibers attach

Anaphase

spindle fibers separate sister chromatids

Telophase

Nuclei form around separated chromosomes

Cytokinesis

cell membrane splits around the nuclei

Clevage furrow

how animal cells split

Cell plate

how plant cells split

homozygote

when an org’s set of alleles for a gene is made of identical alleles

heterozygote

when an org’s set of alleles for a gene is made of different alleles

testcross

breeding an org w/ unknown genetic and a recessive homozygote to find out its genetic makeup

monohybrid

when an org is heterozygous for only one trait

dihybrid

when an org is heterozygous for 2 traits

incomplete dominance

where one allele does not exhibit complete dominance and heterozygotes have a phenotype in between dominant and recessive homozygotes

codominance

two alleles have different effects, and heterozygotes don’t have intermediate phenotype, instead have both phenotypes

pleiotropy

a gene codes for multiple phenotypes

polygenic inheritance

where a multiple genes affect the phenotype

epistasis

when a gene’s phenotype affects a different gene’s phenotype

gonad

Sexual organ

spermatogenesis

creation of sperm

oogenesis

Creation of egg

binary fission

budding

asexual reproduction where a new identical org grows on the person

fragmentation

asexual reproduction where “chopped off” part becomes new identical org

meiosis

diploid parent gamete → 2 diploid daughters → 4 haploid cells

homologous chromosomes/tetrads

pairing of 2 corresponding chromosomes (like they have the same genes (possibly different alleles) ) one from mom one from dad

chiasma

areas where tetrads exchange genes

prophase I meiosis

dna coils into chromosomes then tetrads, genetic info exchanged + normal mitosis prophase stuff

metaphase I meiosis

homologues chromosomes are lined up in the center and attached to the spindle fibers

Anaphase I meiosis

homologus chromosoms split into sister chromatids

Telophase I + Cytokinesis Meiosis

nuclei form around the split chromosomes & cytoplasm splits

nondisjunction

when homologs or sister chromatids fail to separate correctly - may cause genetic disorders.

Virus

Genes with a protein coat

multiple alleles

when multiple alleles control the expression of a gene

sex-linked gene

any gene that is on a x or y chromosome

linked genes

genes that have close loci and are therefore expressed together often bc during DNA crossover they cross over together.

autosome

non-sex chromosome

Autosomal Dominant Pedigree Evidence

• trait appear in both sexes

• trait usually don’t skip generations

Autosomal Recessive Pedigree Evidence

• both genders

• trait may skip generations

• 2 ppl with the trait bred 2gether will never produce other trait

Sex-Linked Dominant Pedigree Evidence

• appears mostly in men

  • same as dominant

Sex-linked Recessive Pedigree evidence

• appears mostly in men

  • same as recessive

wild type

X/Y linked genes

genes on the X/Y chromosomes

Barr Body

One of a female’s chromosomes is deactivated in embryonic development in each cell (randomly) and becomes a Barr Body. It is reactivated during egg formation

mosaicism

if female is heterozygous, bc of X deactivation ~half cells will express one gene and the other half express another → causes cat tortoise shell

parental types

offspring that matches one parent

recombinants

offspring that has new combos of traits

when parental types occurence >50%

liekly linked genes

linkage map

gene map based on recombination frequency (lower freq = closer)

aneuploidy

when zygote receives abnormal amount of chromosome

monosomic

when zygote is missing a chromosome

trisomic

when 3 copies of chromsome in offspring

transformation (genetics)

a way of bacteria increasing genetic diversity by picking up other genes from enviro and expressing them

semi--conservative DNA replication

½ DNA is always original

DNA polymerase

a enzyme that helps start DNA replication by adding new nucleotides from 5’ to 3’ (for new)/ 3’ to 5’ (for originial)

DNA Helicase

an enzyme that unwinds the DNA double helix

Step 1 of DNA replication

DNA helicase splits the double strand & unwinds the dble helix

Step 2 of DNA replication

Binding proteins stop hydrogen bonds so DNA single strands cant go back together

Step 3 of DNA Replication

Topoisomerase prevents DNA snapping by relieving tension on the uncoiled DNA

Step 4 of DNA Replication

Primase puts RNA primers on the 3’ part of DNA so the DNA polymerase knows where to go

Step 5 of DNA Replication

DNA Helicase travels in replication fork and keeps splitting and unwinding the strand

Step 6 of DNA Replication

DNA Polymerase III comes to replicate DNA, causing the leading and lagging strands

leading strand

DNA strand where DNA polymerase goes in the replication fork direction

lagging strand

DNA strand where DNA polymerase goes in opposite direction of replication fork

Okazaki fragments

segments on the lagging strand where the DNA polymerase goes and replicates and then goes backwards to replicate more & so on

Step 7 of DNA Replication

other types of DNA polymerase come back to proofread the DNA & fix any issues. They also replace RNA primer w/ DNA.

Step 8 of DNA Replication

Ligase connect Okazaki fragments & joins the 2 strands of DNA