unit 5 bio

Question 1

Alleles

Answer 1

one of two or more alternative versions or forms of a gene that arise from mutations, occupying the same specific location on a chromosome

Question 2

Aneuploidy

Answer 2

the condition of having an abnormal number of chromosomes in a cell

Question 3

autosomes

Answer 3

any chromosome that is not a sex chromosome

Question 4

barr body

Answer 4

Barr body is a condensed, inactivated X chromosome found in the nucleus of somatic cells in female mammals, appearing as a dark spot, which balances the expression of X-linked genes between sexes by effectively reducing one X chromosome to one single X

Question 5

chiasma

Answer 5

a point at which paired chromosomes remain in contact during the first metaphase of meiosis, and at which crossing over and exchange of genetic material occur between the strands.

Question 6

codominance

Answer 6

a genetic pattern where both alleles from each parent are fully and equally expressed in the offspring’s phenotype, resulting in a trait that shows both parental characteristics distinctly, not blended

Question 7

complete dominance

Answer 7

where one allele (the dominant) completely masks the effect of another allele (the recessive) in a heterozygous individual, resulting in the dominant phenotype being fully expressed, as if the recessive allele weren’t even there

Question 8

crossing over

Answer 8

process during meiosis where homologous chromosomes exchange segments of their DNA, creating new combinations of genes on the chromatids, which significantly increases genetic diversity in gametes and ultimately in offspring, driving evolution and adaptation

Question 9

cystic fibrosis

Answer 9

an inherited genetic disorder caused by a mutation in the CFTR gene, leading to the production of abnormally thick, sticky mucus that clogs airways and ducts in organs like the pancreas, lungs, and liver, causing chronic infections, breathing difficulties, digestive problems, and organ damage over time

Question 10

Depletion

Answer 10

the reduction, loss, or emptying of essential substances like body fluids, nutrients, stored materials, or cells from an organism or ecosystem, often happening faster than they can be replenished, leading to debilitation or resource scarcity

Question 11

diploid cell

Answer 11

a cell containing two complete sets of chromosomes, one inherited from each parent, forming homologous pairs (2n)

Question 12

down syndrome

Answer 12

a chromosomal condition caused by having an extra full or partial copy of chromosome 21, leading to extra genetic material that alters development, causing characteristic physical features, intellectual disabilities, and increased health risks, most commonly due to Trisomy 21 resulting from a cell division error called nondisjunction

Question 13

duchenne muscular dystrophy

Answer 13

a severe, genetic disorder causing progressive muscle degeneration, primarily in boys, due to mutations in the DMD gene, leading to the absence of the crucial dystrophin protein that stabilizes muscle fibers, resulting in rapid weakness, loss of mobility, and eventual reliance on wheelchairs and ventilation, with symptoms starting in early childhood

Question 14

Duplication

Answer 14

a genetic mutation where a segment of DNA, from a single gene to a large chromosomal region, gets copied, creating extra genetic material in the genome

Question 15

Gametes

Answer 15

specialized reproductive cells that carry half the genetic material needed to form a new organism

Question 16

Genome

Answer 16

the complete set of an organism’s genetic material, containing all the instructions needed to build, function, and reproduce that organism, encompassing genes and non-coding sequences organized into chromosomes

Question 17

haploid cell

Answer 17

contains a single set of unpaired chromosomes, meaning it has half the number of chromosomes as a normal diploid body cell

Question 18

Hemophilia

Answer 18

a genetic bleeding disorder where the blood clots too slowly due to a lack or deficiency of essential clotting factor proteins

Question 19

homologous chromosomes

Answer 19

pairs of chromosomes, one from each parent, that are similar in size, shape, and gene sequence, carrying the same genes at the same locations but potentially different versions of those genes

Question 20

Huntington’s disease

Answer 20

a fatal, inherited neurological disorder caused by a mutated gene leading to nerve cell breakdown and death in the brain, resulting in uncontrolled movements, cognitive decline, and psychiatric issues, characterized by a CAG repeat expansion that creates a toxic, abnormal huntingtin protein, damaging neurons over time

Question 21

Hybridization

Answer 21

the process of combining genetic material from two different, distinct individuals through reproduction to create offspring

Question 22

incomplete dominance

Answer 22

a pattern where neither allele for a trait is fully dominant, resulting in a heterozygous phenotype that is an intermediate blend of the two homozygous traits

Question 23

Inversion

Answer 23

a chromosomal mutation where a chromosome segment breaks off, flips 180 degrees, and reattaches, reversing its gene order

Question 24

Karyotype

Answer 24

an individual’s complete set of chromosomes, organized by size, shape, and number, often presented as a visual chart to identify genetic abnormalities like extra or missing chromosomes, which helps diagnose genetic disorders or cancers

Question 25

law of independent assortment

Answer 25

alleles for different genes segregate and are distributed into gametes independently of each other during meiosis

Question 26

law of segregation

Answer 26

during the formation of sex cells, the two alleles for a trait separate, ensuring each gamete receives only one allele, so offspring inherit one allele for each gene from each parent, leading to varied trait combinations

Question 27

linkage map

Answer 27

a genetic map showing the relative positions of genes or markers on a chromosome, determined by how often they recombine during sexual reproduction

Question 28

linked genes

Answer 28

genes located close together on the same chromosome that tend to be inherited together during meiosis because they are less likely to be separated by crossing over

Question 29

Monosomic

Answer 29

a genetic condition where one chromosome from a pair is missing, resulting in 45 chromosomes instead of the usual 46 in humans, often due to an error during cell division

Question 30

Nondisjunction

Answer 30

the failure of homologous chromosomes or sister chromatids to separate properly during cell division

Question 31

parental types

Answer 31

offspring whose combination of alleles or traits is identical to one of the original parents, resulting from the inheritance of linked genes that don't get shuffled during meiosis

Question 32

Pedigree

Answer 32

a diagram showing family relationships and the inheritance of traits or genetic conditions across generations

Question 33

polygenic inheritance

Answer 33

when a single trait, like height or skin color, is controlled by the cumulative effects of multiple genes, not just one, leading to a wide, continuous range of phenotypes instead of distinct categories

Question 34

Polyploidy

Answer 34

the condition where a cell or organism has more than two complete sets of chromosomes, rather than the usual two sets

Question 35

Recombinants

Answer 35

a cell, organism, DNA molecule, or protein that has been formed by combining genetic material from two different sources, often through laboratory techniques or natural processes like sexual reproduction, resulting in new gene combinations not found in the parents, which increases genetic diversity

Question 36

sex linked genes

Answer 36

located on the sex chromosomes leading to inheritance patterns that differ between males and females because they have different sex chromosome combinations

Question 37

sickle cell anemia

Answer 37

an inherited blood disorder where a genetic mutation causes red blood cells, normally round and flexible, to become stiff, sticky, and crescent-shaped

Question 38

somatic cell

Answer 38

any cell in a multicellular organism that isn't a reproductive cell or a stem cell, forming the body's tissues and organs

Question 39

tay sachs

Answer 39

a severe, inherited neurological disorder where a genetic defect causes the body to lack the enzyme hexosaminidase A, leading to toxic buildup of lipids in nerve cells, primarily the brain and spinal cord, resulting in progressive neurological damage, developmental delays, muscle weakness, seizures, and eventual death, usually in early childhood for the common infantile form

Question 40

Tetrad

Answer 40

the structure formed during meiosis where a pair of homologous chromosomes, each already duplicated into two sister chromatids, come together, creating a group of four chromatids

Question 41

Translocation

Answer 41

moving substances or structures from one place to another, most commonly referring to the transport of sugars in plants via the phloem or a genetic rearrangement where chromosome parts swap or attach to different chromosomes, affecting gene function

Question 42

wild type

Answer 42

the most common or "normal" version of a gene, allele, or phenotype found in a natural population