Unit 2: Mendelian and Genetics Flashcards by Khris Manalo

branch of biology that deals with heredity and variation of organisms

genetics

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carry the hereditary information (genes)

chromosomes

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________ -> DNA -> RNA -> proteins

genes

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arrangement of nucleotides in DNA

chromosomes

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contain DNA that codes for the same genes

homologous chromosomes

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homologous regions code for the same _________

gene

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both chromosomes have all the same genes in the same locations but different versions of those genes

homologous chromosomes

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a unit of heredity

gene

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exact replicas of genes

sister chromatids

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two genes that occupy the same position on homologous chromosomes and that cover the same trait

alleles

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a section of DNA sequence encoding a single protein

gene

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the entire set of genes in an organism

genome

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a fixed location on a strand of DNA where a gene or one of its alleles is located

locus

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‘flavors’ of a trait

alleles

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the physical appearance of an organism

phenotype

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the genetic makeup of an organism

genotype

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genotype + environment

phenotype

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having two different genes for a particular characteristic

heterozygous

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having identical genes (one from each parent) for a particular characteristic

homozygous

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trait in which a gene is carried on a sex chromosome

sex-linked

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the trait appears in the heterozygous condition

dominant

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a genetic cross between two different genes that differ in two observed traits

dihybrid cross

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trait controlled by genes on one of 22 pairs of autosomes

autosomal

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the allele of a gene that masks or suppresses the expression of an alternate allele

dominant

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does not appear in the heterozygous condition, only in homozygous

recessive

an allele that is masked by a dominant allele

recessive

first filial generation of a genetic cross

a genetic cross involving a single pair of genes (one trait)

monohybrid corss

THEORY: traits of two parents "blend" together and inherited by the offspring

Blending Theory of Inheritance

a genetic cross where parents differ by a single trait

monohybrid cross

How many traits or characteristics did Mendel observe in pea plants?

parental generation

second filial generation of a genetic cross

plant in Mendel's experiment

pea plants

Enumerate the 7 traits or characteristics of pea plants observed in Mendel's Experiment

round / wrinkled yellow / green purple / white petals axial / terminal flowers yellow / green unripe pods inflated / pinched ripe pods long / short stems

aka Mendel's theory

Particulate Theory of Inheritance

aka the gene idea

Particulate Theory of Inheritance

THEORY: inheritance involves the passing of discrete units of inheritance, or genes, from parents to offspring

Particulate Theory of Inheritance

Who proved the Chromosome Theory of Inheritance?

Thomas Morgan

Who proposed the Chromosome Theory of Inheritance?

Walter Sutton

What was the subject used in proving the Chromosome Theory of Inheritance?

fruit fly

Enumerate the 3 patterns of inheritance

Principle of Dominance Principle of Segregation Principle of Independent Assortment

THEORY: genes are present within chromosomes inside the cell

Chromosome Theory of Inheritance

POI: one allele masked another, one allele was dominants over the other in the F1 generation

Principle of Dominance

THEORY: genes and chromosomes are in pairs in diploid cells

Chromosome Theory of Inheritance

POI: When gametes are formed, the pairs of hereditary factors (genes) become separated, so that each sex cell (egg/sperm) receives only one kind of gene

Principle of Segregation

POI: genes located on different chromosomes will be inherited independently of each other

Principle of Independent Assortment

a useful tool to do genetic crosses

punnett square

a lethal genetic disease affecting Caucasians

Cystic Fibrosis

used to determine the probability of outcome of offspring

punnett square

looks like a windowpane

punnett square

Cystic Fibrosis is caused by mutant ___________ gene carried by 1 in 20 people of European descent

recessive

1 in _____ children will have Cystic Fibrosis from 2 parent carriers

Cystic Fibrosis affects _________ in tissues

transport

Enumerate the steps in making a punnett square

1. determine the genotypes of the parent organisms 2. write down your "cross" (mating) 3. draw a Punnett square 4. put in the genotype of one parent across the top and that of the other parent down the left side 5. fill in the boxes by copying the row and column head letters across or down into the empty squares

1 in ______ Caucasian couples will be both carriers of Cystic Fibrosis

400

Huntington Disease is also known as _________ because every child of a parent with HD has a 50/50 chance of inheriting the faulty gene

quintessential family disease

In Cystic Fibrosis, ___________ is accumulated in lungs, causing infections

mucus

a fatal genetic disorder that causes the progressive breakdown of nerve cells in the brain

Huntington Disease

The allele for Huntington Disease is _________

dominant

mating that involve parents that differ in two genes (two independent traits)

dihybrid cross

If F1 generation is allowed to self-pollinate, Mendel observed ________(#) phenotypes

Test cross with a _____________ individual

homozygous recessive

performed when you have an individual with an unknown genotype

test cross

type of relationship between alleles, with a heterozygote phenotype intermediate between the two homozygote phenotypes

Incomplete Dominance

When F1 generation is self-pollinated, the F2 generation ratio is __________

1:2:1

colorblindness is an example of a ___________ trait

sex-linked

colorblindness gene is carried only by _____ sex chromosome

In colorblindness, the Y chromosome is _________ than the X chromosome and contains only limited genes

shorter

autosomal traits that are influenced by sex

sex-influenced

Sex-influenced traits: if a male has one __________ allele, he will show that trait, but it will take _________ recessive for the female to show that same trait

recessive 2

both alleles are simultaneously expressed in the heterozygote

codominant traits

genes that are likely to be inherited together because they are physically close to one another on the same chromosome

linked genes

an example of codominant traits is __________

blood type

a section of DNA sequence encoding a single protein

Gene

the entire set of genes in an organism

genome

two genes that occupy the same position on homologous chromosomes and that cover the same trait

Alleles

Like 'flavors' of a trait

alleles

a fixed location on a strand of DNA where a gene or one of its alleles is located

locus

genetic makeup of an organisms

genotype

physical appearance of an organism

Phenotype

Genotype + Environment

Phenotype

Having identical genes (one from each parent) for a particular characteristic

Homozygous

having two different genes for a particular characteristic

Heterozygous

a Trait in which a gene is carried on a sex chromosome

Sex-linked trait

traits controlled by genes on one of 22 pairs of autosomes

Autosomal trait

the allele of a gene that masks or suppresses the expression of an alternate all

dominant

the trait appears in the heterozygous condition

DOminant

An allele that is masked by a dominant allele

Recessive

Does not appear in the heterozygous condition, only in homozygous

Recessive

a genetic cross involving a single pair of genes (one trait); parents differ by a single trait

Monohybrid

a genetic cross between two different genes that differ in two observed traits

Dihybrid Cross

What does this mean? (P)

Parental generation

What does this mean? (F1)

First filial generation; offspring from a genetic cross

What does this mean ? (F2)

Second filial generation of a genetic cross

It is when you follow strictly the Punnett Square

Single gene disease -- Mendelian gene/trait

most common expression of a particular allele combination in a population. It may be recessive or dominant ex. Black hair for all Asian (Filipinos)

Wild type phenotype

Variant of a (wild type) gene's expression that arises when the gene undergoes a change, or mutation Nahaluan ung Wild type Pheno, ex. Blonde Asian/FIlipino

Mutant Phenotype

An illness that typically begins in early adulthood, causing uncontrollable movements and changes in behavior and thinking (cognition), with death 15 to 20 years later

Huntington disease

How many percent of people who have HD are under age 20.

10%

# Characteristics of Single-Gene Diseases In families, we can deduce the probability that a particular person has inherited a single-gene disease by considering how he or she is related to an affected relative. | By using what?

Punnett Square

T/F: Genes do not like or dislike certain types of people; rather, mutations stay in certain populations because we tend to have children with people similar to ourselves.

True

2 example of single-gene diseases

Sickle cell disease Muscular dystrophy

Many single- gene diseases affect fewer than ___ in 10,000 individuals.

This consist of sick children and their parents can reveal whether the child inherited two disease-causing mutations from carrier parents, or whether a dominant mutation arose anew, termed "*de novo*"

Tests of trio

What do you call ung wala sa genetics nila pero nagkaroon sya like sya ung nauna?

*de novo*

Traits of two parents “blend” together and inherited by the offspring

Blending Theory of Inheritance

Particulate Theory of Inheritanceis aka the _____________

Gene Idea

Chromosome Theory of Inheritance is Proposed by ________ and proved by ___________ using _________.

Proposed by Walter Sutton Proved by Thomas Morgan using fruit fly

# Chromosome Theory of Inheritance Genes and chromosomes are in pairs in (diploid/haploid) cells

Diploid cells

# What pattern of Inheritance? One allele masks another, one allele was dominant over the other in the F1 generation.

Principle of Dominance

# What type of Patterns of Inheritance? When gametes are formed, the pairs of hereditary factors (genes) become separated, so that each sex cell (egg/sperm) receives only one kind of gene.

Principle of Segregation

# What type of Patterns of Inheritance? Genes located on different chromosomes will be inherited independently of each other.

Principle of independent assortment

Mendel noted that short plants crossed to other short plants were “true-breeding," | What does it mean?

always producing the same phenotype, in this case short plants.

# Huntington's Disease Some dominantly inherited diseases are said to be due to a (“lose/gain-of-function,”) because they result from the action of an abnormal protein that interferes with the function of the normal protein. | extra protein they produce interfering in their nerves ## Footnote Huntington disease results from a (lose/gain-of-function) in which the dominant mutant allele encodes an abnormally long protein that prevents the normal protein from functioning in certain brain cells.

“gain-of-function”

# Homozygous/Hetereozygous They can supply half the recessive allele. They will have mid-way amount of enzymes

Heterozygous

An individual with two different recessive alleles for the same gene is termed what? | Some people who have inherited diseases

compound heterozygote.

Child has a recessive allele from each parent with the variant located at a different position within the same gene

Compound Geterozygous (CH) Variants

# How is nucleotide inheritance determines? In terms of Laboratory-based?

10x Genomics or fosmid pool-based startegy

# How is nucleotide inheritance determines? In terms of Computer-based?

SHAPEIT2,Beagle, Eagle2,HapCUT2

# Why study CH variants? CH variants are understudied in ___________ disease

Pediatric disease

# Why study CH variants? May contribute to ________onset

Early disease onset

was the first genetic disorder for which mass post-natal genetic screening was available, beginning in the early 1960s, atypical cases were detected almost immediately. a. Phenylketonuria b. Tay–Sachs disease c. Sickle cell syndromes

Phenylketonuria

Molecular analysis of the genome was not yet possible, but protein sequencing revealed cases caused by compound heterozygosity a. Phenylketonuria b. Tay–Sachs disease c. Sickle cell syndromes

a. Phenylketonuria

disease may present in juvenile or adult onset forms, often as the result of compound heterozygosity between two alleles, one that causes the classic infantile disease in homozygotes and another that allows some residual HEXA enzyme activity. a. Phenylketonuria b. Tay–Sachs disease c. Sickle cell syndromes

Tay–Sachs disease

A variety of sickle cell disorders result from inheritance of the sickle cell gene in a compound heterozygous manner with other mutant beta globin genes a. Phenylketonuria b. Tay–Sachs disease c. Sickle cell syndromes

Sickle cell syndromes

. These disorders include sickle cell-beta thalassemia. In the case of sickle cell anemia, an individual with one allele for hemoglobin S and one allele for hemoglobin C would still develop the disease, despite being heterozygous for both genes. a. Phenylketonuria b. Tay–Sachs disease c. Sickle cell syndromes

c. Sickle cell syndromes

A recessive trait is said to arise from a “loss/gain-of-function” because the recessive allele usually prevents the production or activity of the normal protein

“loss-of-function”

# On the RECESSIVENESS principle The one normal allele, therefore, compensates for the mutant one, to which it is dominant/recessive.

dominant

# On the RECESSIVENESS principle T/F: The basis of an inborn error of metabolism is easy to picture. These diseases are typically recessive because the half normal amount of the enzyme that a carrier produces is usually sufficient to maintain health. The one normal allele, therefore, compensates for the mutant one, to which it is dominant.

TRUE

# On the RECESSIVENESS principle Recessive diseases tend to be more severe, and produce symptoms earlier, than dominant diseases. Disease-causing recessive alleles remain in populations because healthy heterozygotes pass them to future generations.

True

# On the RECESSIVENESS principle Most autosomal recessive conditions appear unexpectedly in families, because they are transmitted silently, through (homozygotes/heterozygotes) (carriers)

heterozygotes

# On the RECESSIVENESS principle Marriage between relatives introduces ________, which means “shared blood”—a figurative description, because genes are not passed in blood.

consanguinity

# On the RECESSIVENESS principle Alleles inherited from shared ancestors are said to be “________________________”

identical by descent.

# Comparison of Autosomal Dominant and Autosomal Recessive Inheritance Males and females affected, with equal frequency. a. Autosomal Dominant b. Autosomal Recessive c. Both

Both

# Comparison of Autosomal Dominant and Autosomal Recessive Inheritance Successive generations affected until no one inherits the mutation a. Autosomal Dominant b. Autosomal Recessive c. Both

# Comparison of Autosomal Dominant and Autosomal Recessive Inheritance Affected individual has an affected parent, unless he or she has a *de novo* mutation a. Autosomal Dominant b. Autosomal Recessive c. Both

# Comparison of Autosomal Dominant and Autosomal Recessive Inheritance Can skip generations a. Autosomal Dominant b. Autosomal Recessive c. Both

# Comparison of Autosomal Dominant and Autosomal Recessive Inheritance Affected individual has parents who are affected or are carriers (heterozygotes) a. Autosomal Dominant b. Autosomal Recessive c. Both

Mendel's 1st law | reflects d actions of chromosomes nd d genes they carry during meiosis. ## Footnote (An individual with two identical alleles for a gene is homozygous for that gene. An individual with two different alleles is heterozygous—what Mendel called “non-true-breeding” or “hybrid.”)

Law of Segregation

# Mendel’s 1st Law Gametes combine at random. A t-bearing oocyte is neither more nor less attractive to a sperm than is a T-bearing oocyte. These two factors—equal allele distribution into gametes and random combinations of gametes— underlie Mendel's Law of _______

Segregation

Mendel’s 2nd Law is what?

Law of independent assortment

# Mendel's 2nd Law states that for two genes on different chromosomes, the inheritance of one gene does not influence the chance of inheriting the other gene ## Footnote The two genes are said to “independently assort” because they are packaged into gametes at random.

Law of Independent assortment ## Footnote Two genes that are far apart on the same chromosome (see discussion on linkage) also appear to independently assort, because so many crossovers take place between them that it is as if they are part of separate chromosomes

What is Principle 1? a. Test cross/ Pedigree analysis b. Punett square - Single test cross/monohybdrid c. Dihybrid Cross

Law 1 a. Test cross/ Pedigree analysis b. Punett square - Single test cross/monohybdrid c. Dihybrid Cross

Law 2 a. Test cross/ Pedigree analysis b. Punett square - Single test cross/monohybdrid c. Dihybrid Cross

■ A useful tool to do genetic crosses ■ Looks like a windowpane ■ Used to determine the probability of outcome of offspring

Punnett Square

a lethal genetic disease affecting Caucasians. | 1 in 400 Caucasian couples will be both carriers of CF, 1 in 4 children ## Footnote Caused by mutant recessive gene carried by 1 in 20 people of European descent. affects transport in tissues – mucus is accumulated in lungs, causing infections.

Cystic Fibrosis(CF)

a fatal genetic disorder that causes the progressive breakdown of nerve cells in the brain | allele for Huntington's disease is dominant ## Footnote known as the quintessential family disease because every child of a parent with HD has a 50/50 chance of inheriting the faulty gene

Huntington Disease (HD)

Mating that involve parents that differ in two genes (two independent traits) ## Footnote For example, flower color: P = purple (dominant) p = white (recessive) and stem length: T = tall t = short

Case: Huntington Disease (HD) Dihybrid Cross

When you have an individual with an unknown genotype, you do a ______. | Cross with a homozygous recessive individual. ## Footnote For example, a plant with purple flowers can either be PP or Pp… therefore, you cross the plant with a pp (white flowers, homozygous recessive)

Test cross

Unit 2: Mendelian and Genetics Flashcards

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