unit 5 biology test

for 5/2/23

who was gregor mendel?

the “father of genetics”

define: chromatin

dna in thin strands

define: chromosome

chromatin coiled around protein forming an X shape

what does a chromosome consist of?

two sister chromatids joined by a centromere

define: gene

a DNA segment that codes for a trait

define: character

an inheritable physical feature

define: trait

a variation of a character

define: allele

a different version of a gene

define: dominant allele

the stronger gene that physically shows on an organism

define: recessive allele

the weaker gene that does not physically show on an organism

define: homozygous

the organism either has two dominant alleles or two recessive alleles

define: heterozygous

the organism has one dominant and one recessive allele

define: phenotype

the physical trait that can be seen

define: genotype

the genetic combination for a trait

define: punnett square

a chart showing possible genetic outcomes for a child

where does the mothers genotype go on a punnett square?

the left side

where does the fathers genotype go on a punnett square?

the top

define: mendels law of segregation

to separate the two alleles of one parent

define: law of independent assortment

chromosomes line up independently from each other so that genes from different chromosomes do not affect each other

when does the law of segregation occur?

during anaphase 1 and 2 of meiosis

when does the law of independent assortment occur?

during metaphase 1 and anaphase 1 of meiosis

define: complete dominance

the dominant allele is only expressed all the way

define: incomplete dominance

both alleles are expressed and blended together

define: codominance

both alleles are expressed and are equally present but separate

define: multiple alleles

when there are multiple versions of the same allele

define: pedigree

a chart showing the family history of a specific trait

what shape are males in pedigrees?

squares

what shape are females in pedigrees?

circles

what does it mean when a shape on a pedigree is shaded in?

that person has the trait

what does a horizontal line between two people mean on a pedigree?

a breeding couple

what does a vertical line between two people mean on a pedigree?

offspring

name a recessive disorder

cystic fibrosis, sickle-cell disease

name a dominant disorder:

dwarfism, huntingtons disease

define: locus

the location of a gene on a chromosome

define: genome

organisms complete dna sequence

define: asexual reproduction

one parent making a clone of itself

name benefits of asexual reproduction

quick reproduction, only one parent needed

name disadvantages of asexual reproduction

no genetic variation, massive death rate

define: sexual reproduction

two parents combining dna resulting in different offspring

name benefits of sexual reproduction

variation in offspring, evolution over time

name disadvantages of sexual reproduction

takes two parents, takes longer

define: somatic cells

regular body cells

how do somatic cells reproduce?

mitosis

define: germ cells

sex cells

how do germ cells reproduce?

meiosis

define: trisomy

too many chromosomes

define: monosomy

too few chromosomes

why are microinsertions and microdeletions hard to see on a microscope?

they’re too small

define: homologous

identical chromosomes

define: heterogous

chromosome pair that is different

does mitosis make haploid or diploid cells?

diploid

does meiosis make haploid or diploid cells?

haploid

define: haploid

having only one set of chromosomes

define: diploid

having two sets of chromosomes

what happens in meiosis 1?

the 46 chromosomes are separated

what phases are in meiosis 1?

interphase, prophase, metaphase, anaphase, telophase

what happens in meiosis 2?

the sister chromatids are separated into four daughter cells

what phases are in meiosis 2?

prophase 2, metaphase 2, anaphase 2, telophase 2, cytokenisis

define: crossover

the male and female chromosomes swapping genes

when does the crossover occur?

prophase 1

what is the purpose of crossover?

genetic variation

how has genetic variation evolved?

prophase 1-crossover, metaphase 1-independent assortment, anaphase 1-law of segragation

define: sex linked gene

genes only passed down through x sex chromosome

is colorblindness dominant or recessive?

recessive

what kind of disorder is colorblindness?

sex linked

is hemophilia recessive or dominant?

recessive

define: karyotype

a picture of all a persons chromosomes

when is karyotype taken?

metaphase

how many pairs of chromosomes do humans have?

23

what is the first step to creating a karyotype?

collect cells and place in petri dish, add cyclin and make cells go into mitosis

what is the second step to creating a karyotype?

allow cells to continue dividing until metaphase, then add chemical to stop mitosis

what is the third step to creating a karyotype?

add dye to chromosomes to stain genes and create banding pattern

what is the fourth step to creating a karyotype?

take picture of chromosomes through microscope

what is the fifth step to creating a karyotype?

cut out chromosomes and arrange them largest to smallest

what is the first step in interpreting a karyotype?

length of chromosomes

what is the second step in interpreting a karyotype?

centromere position

what is the third step in interpreting a karyotype?

banding pattern

what is the fourth step in interpreting a karyotype?

locus of gene

define:

telocentric

define:

acrocentric

define:

submetacentric

define:

metacentric

define: top and short arm of a chromosome

p arm

define: bottom and long arm of a chromosome

q arm

define: aneuploidy

having the wrong number of chromosomes

define: polyploidy

having many extra sets of chromosomes

define: 3N

three sets of each chromosome

define: 4N

four sets of each chromosome

define: part of a chromosome segment is missing

deletion

define: a chromosome segment was copied twice. two genes on the same chromosome and one missing on the other

duplication

define: a chromosome segment is backwards

inversion

define: a chromosome segment is attached to a different autosome; not where it should be

translocation

what is the first stage of mitosis?

interphase

what is the second stage of mitosis?

prophase

what is the third stage of mitosis?

metaphase

what is the fourth stage of mitosis?

anaphase

what is the fifth stage of mitosis?

telophase

what is the sixth stage of mitosis?

cytokenesis

what are the three sub-stages of interphase?

G1, S, G2

what happens in interphase?

growth, copy DNA, self check