Bio 111 Test #4 Vocab

mitosis

the process of cell division that creates two identical daughter cells.

prophase

where chromosomes condense into x-shaped structure, the nucleus disappears, and mitotic spindle begins to form

prometaphase

when the nuclear envelope completely breaks down to allow the spindle microtubules to go into the nuclear area, and kinetochores (special protein) develop at the centromere to allow spindle fibers to attach.

metaphase

where the chromosomes align along the center of the cell creating a plane called metaphase plate, each sister chromatid is attached to a spindle fiber from opposite poles.

anaphase

where cohesion holding the sister chromatids are broken and the sister chromatids are pulled apart towards the opposite poles of the cell.

telophase

when the chromosomes arrive at opposite poles to uncoil, and two new nuclear membranes form around the chromosomes.

sister chromatids

two identical halves of a single replicated chromosome.

daughter chromosmes

sister chromatids after cell division of anaphase where they become independent structures.

sister chromatids vs. daughter chromosomes

the differences are is one is X shape, present from s phase until pulled apart in anaphase, one centromere holds both chromatids together, and chromatids genetically identical. while the other are its own chromosome, formed during anaphase and exist to telophase, each daughter chromosome has its own centromere, and is genetically identical to one another to form identical daughter cells.

cell cycle

consists of interphase and mitosis where the cell grows, copies DNA, and divides.

G1

when the cell grows, performs daily functions, and creates proteins. Passes a checkpoint to ensure it's healthy and ready to replicate DNA.

S

when the cell replicates and duplicates its genetic material and each chromosome is duplicated to produce two sister chromatids.

G2

when the cell grows more, creates proteins for division, and makes final preparations for division. Passes another checkpoint to make sure DNA was replicated properly.

M

M is when cell division occurs and creates two identical daughter cells that restarts the cycle.

mitotic spindle

aptures chromosomes and align them at the cell’s center, pull sister chromatids apart, and ensure cells receive identical copies.

centromeres

The anchor for the cell during division. Centromeres hold sister chromatids together until ready to be pulled apart, kinetochores (special protein) assemble at the centromere and act as hooks for spindle fibers, and pull apart DNA copies to the opposite end of the dividing cell.

cleavage furrow

an indentation that tightens to pinch the cell to help with cytokinesis.

MPF

a protein complex that acts as a switch from a cell’s transition from G2 to M phase. It impacts the cell cycle by transferring phosphate groups to multiple target proteins to alter their function. When it’s activated it may allow the cell to carry out the M phase.

cyclin

 regulatory protein that controls the cell cycle. It’s related to MPF because it binds to cyclin-dependent kinase that powers MPF. Specifically, it builds up to a certain concentration as the cell prepares to divide and binds to CDK. Next, the binding changes the kinase shape to form the new complex, MPF, that will transfer phosphate groups to various target proteins.

cancer cells

cells that abnormally grow and harm the body

cancer cells vs. normal cells

Cancer cells bypass the cell cycle and immune system checkpoints. Normal cells mature, divide, and die; while cancer cells remain immature, divide quickly, and avoid death by preventing apoptosis (programmed death). Normal cells go through checkpoints to ensure cell stability; while cancer ignores checkpoints and divides damaged DNA. Normal cells have a division limit that they know based on their telomere length (shortens after division); while cancer cells can stimulate their division by reactivating telomerase or rebuilding their telomere which is why cancer cells can be called immortal. Normal cells will stop dividing when encountering other cells or running out of external growth signals, but cancer cells stimulate their growth and ignore density barriers. Normal cells will stay where they are supposed to be, but cancer cells can detach from the primary tumor, travel through the bloodstream, and form new tumors in other organs.

sexual reproduction

needs two parents to produce unique offspring through mixing of gametes.

asexual reproduction

involves a single parent that produces offspring that are genetically identical clones.

asexual reproduction vs. sexual reproduction

it occurs during the mitosis phase of the cell cycle. The cell goes through prophase, metaphase, anaphase, telophase, and then cytokinesis where two identical clone cells are created. while this is a special meiosis phase will occur to replace mitosis. Meiosis is split into two rounds: meiosis I and II which creates four genetically diverse haploid cells.

homologous pairs

pairs of chromosomes is when one matching chromosome comes from mom and dad each. Each pair decides the same genetic traits, but genetic diversity occurs through varied gene versions.

karyotype

Shows an individual’s complete set that are grouped by size, shape, and banding pattern. This tool can be used to diagnose chromosomal disorders like down syndrome or klinefelter syndrome.

chromatids

one half of a replicated chromosome

chromosome

a x-shaped DNA structure that carries genetic material

meiosis

a two-step cell division that creates unique haploid gametes.

prophase I

where chromosomes condense, pair with homologous chromosomes, and exchange of generic material through crossing over (nuclear membrane breaks down)

metaphase I

where homologous chromosome pairs align at the center and attach to spindle fibers

anaphase I

occurs where homologous chromosomes are pulled apart to opposite poles by spindle fibers and sister chromatids remain attached

telophase I

where chromosomes arrive at opposite poles, new nuclei form, and the cell divides into two  genetically different daughter cells.

prophase II

where chromosomes condense again into two new cells, new spindle fibers form, and nuclear envelope breaks down

metaphase II

occurs where individual chromosomes line up at the center and spindle fibers attach to the chromosomes

anaphase II

where sister chromatids are pulled apart to opposite poles by spindle fibers

telophase II

occurs where nuclear membrane reform around separated chromatids, cells divide, and four unique haploid daughter cells are created.

independent assortment

random distribution of chromosomes and alleles into gametes during meiosis. The importance is because it drives genetic diversity by creating millions of unique genetic combinations. This can happen because chromosome pairs separate during meiosis which allows traits to be inherited independently of one another.

monohybrid cross

Genetic mating experiment used to track the inheritance of a single trait.

dihybrid cross

Genetic experiment that tracks inheritance of two different traits at the same time.

F1 Generation

The first generation of offspring produced from pure-bred parents. The parents are called P generation which are purebreeds or homozygous, but one parent has dominant and the other parent has recessive traits. This generation is completely heterozygous where they carry the dominant and recessive alleles, but the dominant allele is expressed over the recessive allele. Genotype and phenotype ratio 1:1.

F2 Generation

The second generation of offspring produced from the F1 generation. The offspring can be homozygous dominant, homozygous recessive, or heterozygous in a genotypic ratio of 1:2:1 and a phenotypic ratio of 3:1.

F3 Generation

The third generation of offspring produced from the F2 generation. There is a wide variety of trait combinations that could occur with the F2 generation, so the traits of this generation could vary.

Dominant traits

expressed when you inherit one copy of the inherited gene from a parent. Can appear in homozygous dominant or heterozygous offspring.

Recessive traits

traits need two copies of the gene, and one from each parent to be expressed. Can only appear in homozygous recessive offspring.

punnet square

A visual representation of predicting the probability of offspring inheritance of genes based on the genes of two parents. They work by dominant alleles being represented by capital letters and recessive alleles being represented by lowercase letters, the genotype is the letters and genes expressed, and the phenotype is the physical trait that can be seen. The steps to creating one include: writing down the genotypes of both parents, creating a square with four spots, writing one parent’s gene on the top and the other on the left, and filling in the grid using the parent’s alleles.

genotype ratio

the numerical representation of different genetic combinations possible for an offspring.

phenotype ratio

the numerical frequency of observable traits.

Incomplete Dominance

Type of inheritance where neither allele is dominant over the other. What results is a blend of both alleles that creates a new phenotype (e.g., homozygous red and white flowers cross pollinate and create offspring of blended heterozygous pink flowers.)

Polygenic Inheritance

Type of inheritance where a single trait is controlled by two or more genes. These genes can have small cumulative effects that create a spectrum of phenotypes. (e.g., height and skin color because there are many phenotypic variations with these physical traits.)

Pleiotropy

Type of inheritance where a single gene influences multiple traits. A single gene can create a cascading effect that alters multiple physical, behavioral, or biochemical traits. (e.g., PKU is a mutation in the PAH gene that disrupts the breakdown of amino acids that creates multiple problems such as toxic buildup that can lead to intellectual disability, delayed growth, and lack of melanin.)

Codominance

Type of inheritance pattern where two different alleles for a single gene are both fully expressed in the offspring’s physical characteristic. Neither allele mask over the other and both traits are visible. (e.g., human blood type where a father with blood type A and mother with blood type B could create offspring with blood type AB.)

ABO blood types

Dominant, Recessive: Human blood system that is based on the absence or presence of A and B antigens along with Rh factor. Can be used to determine transfusion compatibility. Blood type A and B are dominant over blood type O, but show codominance with each other that creates blood type AB. In addition, Rh positive is dominant over Rh negative.

Rh Factor

An inherited protein found on the surface of red blood cells. If you have the Rh protein then you’re positive; if you don’t have the Rh protein then you’re negative. This information is critical to know for blood transfusions and pregnancies.

Inheritance

The process of passing DNA to children by parents. The DNA is packaged by chromosomes which contain genes that instruct your body’s growth, function, and development. You inherit two copies of every gene from each parent that can determine the chance of having a genetic or complex disorder, physical characteristics (like eye color and height), and environment, diet, lifestyle can impact genes too.

X-linked traits

sex linked traits that are controlled by genes located on the X chromosome. Males and females are affected differently because males have one X chromosome and females have two X chromosomes. If a male inherits a mutated gene on their X chromosome there is no second X chromosome that could carry the non mutated gene which means males are more likely to be affected by x-linked recessive genetic disorders.

SRY gene

An important gene on the Y chromosome that drives male development. For mammals it triggers the creation of testes in embryos to default from the female pathway. Variations can create genetic disorders like Swyer syndrome where a person has X and Y chromosomes, but develop with female characteristics.

Crossing Over

The process where homologous chromosomes exchange segments of DNA during prophase I of meiosis. The exchange specifically occurs between non-sister chromatids to create new combinations of alleles. The importance of crossing over is creating genetically varied offspring with a blend of traits from both parents and the advantageous traits will continue to be passed down to help the species.

Linkage

Genes close to each other on the same chromosome may be inherited together during cell division. These genes may bypass standard independent assortment and travel together. Other important info can be that physical distance determines how likely genes are to stay linked and biologists use recombination frequencies to map relative positions of genes on chromosomes.

Deletion

when chromosomes break and segments of DNA are lost which can lead to developmental disorders. (e.g., parts missing in the short arm for chromosome 5 causes Cri-du-chat syndrome.)

Inversion

when breaks in two places and the segments flip 180 degrees over (reverse) and reattach. No DNA is lost, but can still disrupt genes at breakpoints. (e.g., flipping can occur at chromosome 2 with no significant health effects, but higher risk of infertility, repeated miscarriages, and unbalanced offspring.)

Translocation

occurs when a piece of a chromosome breaks off and attaches itself to a different non-homologous chromosome. If genetic material is swapped and nothing is missing then it’s balanced; if genetic material is swapped and the exchange is unequal, then it’s unbalanced and may cause (e.g., Robertsonian swapping between chromosomes 14 and 21 can be a cause for down syndrome.)

Duplication

the abnormal copying of a segment of a chromosome which results in extra copies of genetic material. Excess DNA can cause an imbalance that overexpresses certain proteins and disrupts cellular functions. (e.g., copying of chromosome 17 is responsible for Charcot-Marie-Tooth disease.)

Insertion

occurs when one or more nucleotide bases are added to a DNA sequence. This can disrupt the reading frame and produce a nonfunctional protein. (e.g., cystic fibrosis can be caused by a three-pair addition that disrupts the CFTR protein.)

Triple X syndrome

Affects genetic females, with characteristics often including taller than average height, learning disabilities, and typical fertility.

Turner Syndrome

Affects genetic females who are missing one entire or partial X chromosome. It is characterized by short stature, ovarian failure, a webbed neck, and heart or kidney defects.

Down Syndrome

Caused by an extra copy of chromosome 21. It leads to varying degrees of intellectual disability, distinct facial features, and a higher risk for congenital heart defects.

Edwards Syndrome

Involves an extra copy of chromosome 18. It causes severe intellectual disability and multiple physical abnormalities, including heart defects and organ malformations.

Patau Syndrome

Results from an extra copy of chromosome 13. It is associated with severe intellectual disability, physical defects like cleft lip/palate, and heart problems.

X-linked punnet square

track genes for the X chromosome and Females have two X chromosomes and males have one X chromosome and that will be seen. Males will be more susceptible to x-linked recessive disorders due to having one X chromosome. Versus, females who can be carriers of x-linked recessive disorders due to having two X chromosomes.