Lesson 4: Human Chromosomes and Chromosome Behavior

Question 1

the structures of chromosome can be best seen during

Answer 1

cell division

Question 2

most common
autosomal trisomy

Answer 2

trisomy 21

Question 3

The chromosomes with satellite are known as

Answer 3

sat-chromosome

Question 4

it binds to DNA and wraps it into coiled loops and we get the compacted chromosome

Answer 4

condensin

Question 5

A very long DNA molecule and associated proteins, that carry portions of the hereditary information of an organism

Answer 5

chromosomes

Question 6

has an intellectual disability and a risk of Alzheimer’s

Answer 6

Trisomy 21

Question 7

Overlapping fingers, low-set ears, decreased muscle tone, heart/lung abnormalities, small physical size, and clubfeet

Answer 7

trisomy 18

Question 8

DNA-protein complex organized into nucleosomes

Answer 8

chromatin

Question 9

Karyotype:
47, XXX

Answer 9

Triple X Syndrome

Question 10

extra segment

Answer 10

duplication

Question 11

When an individual has more than two chromosomes instead of a pair, the condition is called

Answer 11

trisomy

Question 12

Chromatin further condenses with the help of protein known as

Answer 12

condensin

Question 13

Chromosome is composed of:

Answer 13

DNA and histone proteins

Question 14

Clinical features:
* Short stature
* Webbed neck
* Low posterior hairline
* Shield chest
* Amenorrhea
* Absence of puberty
* The early loss of ovarian function (ovarian dysgenesis)
* Infertility
* Skeletal abnormalities (i.e., cubitus valgus),
* Lymphedema
* Congenital kidney and/or heart disease (i.e., horseshoe kidney, coarctation of the aorta)

Answer 14

Turner Syndrome

Question 15

Some cases may seem
phenotypically normal

Answer 15

Triple X Syndrome

Question 16

Approximately 1:1000
male births

Answer 16

XYY Syndrome

Question 17

Clinical features:
Characteristic facial appearance, flat facies, prominent epicanthic folds, weak muscle tone at birth, single transverse palmar crease (simian crease), clinodactyly, congenital digestive and cardiac defects, intellectual disability, increased risk for leukemia, Alzheimer disease and hearing an vision problems

Answer 17

trisomy 21

Question 18

Chromatin is made up of

Answer 18

DNA, RNA, and proteins

Question 19

Chromosome is made up of

Answer 19

chromatin

Question 20

As with triple X syndrome, some cases may seem phenotypically normal.

Answer 20

XYY Syndrome

Question 21

Telomeres are ____, which prevents the fusion of chromosomal segments

Answer 21

polar

Question 22

characteristic facial features, web of skin, constriction of aorta, poor breast development, under-developed ovaries

Answer 22

Triple X Syndrome

Question 23

happens when there is a rearrangement of a chromosome that breaks off then reattaches in the original breakpoints

Answer 23

inversions

Question 24

Approximately 1/3000
to 1:5000 live births

Answer 24

trisomy 18

Question 25

it is a technique to study the structure of chromosomes present in a species

Answer 25

karyotyping

Question 26

Other term for Trisomy 18

Answer 26

Edward's Syndrome

Question 27

Germ cells

Answer 27

23 chromosomes (one copy of each autosome plus a single sex chromosome)

Question 28

Contains how many genes that can precisely code for several proteins in the cell.

Answer 28

hundreds and thousands

Question 29

clinical features: small head, absent eyebrows, cleft lip and/or palate, dysplastic or malformed ears, clenched hands and polydactyly, or extra fingers, undescended or abnormal testes

Answer 29

trisomy 13

Question 30

other term for trisomy 21

Answer 30

Down Syndrome

Question 31

types of chromosome based on the position of the centromere

Answer 31

1. Telocentric 2. Acrocentric 3. Submetacentric 4. Metacentric

Question 32

Clinical features: Presents with increased height and risk of learning disabilities, delayed development of speech, language, and motor skills, weak muscle tone, behavioral and emotional difficulties, seizures, kidney abnormalities

Answer 32

Triple X Syndrome

Question 33

are the basic unit of chromatin.

Answer 33

nucleosomes

Question 34

identical copies of DNA

Answer 34

chromatids

Question 35

tall stature, tendency to lose hair, poor beard growth, female pattern or fat distribution, female-type pubic hair pattern, testicular atrophy

Answer 35

Klinefelter Syndrome

Question 36

Approximately 1:700 to 1/800 live births

Answer 36

trisomy 21

Question 37

When an individual is missing one of the chromosomes from a pair, the condition is called

Answer 37

monosomy

Question 38

Clinical features: Increased height and risk of learning disabilities, delayed development of speech, language, and motor skills, weak muscle tone, hand tremors, seizures, asthma, scoliosis, behavioral and emotional difficulties

Answer 38

XYY Syndrome

Question 39

protect chromosome ends

Answer 39

telomeres

Question 40

second most common autosomal trisomy

Answer 40

trisomy 18

Question 41

Karyotype: 47, XX or XY, +18

Answer 41

Trisomy 18

Question 42

Approximately 1 in 2000 to 1 in 2500 live female births

Answer 42

Turner Syndrome

Question 43

Karyotype: 47, XYY

Answer 43

XYY Syndrome

Question 44

severe intellectual disability, also has heart defects

Answer 44

trisomy 13

Question 45

links sister chromatids

Answer 45

centromere

Question 46

Approximately 1/1000 female births

Answer 46

Triple X Syndrome

Question 47

Normal human somatic cells

Answer 47

46 chromosomes (22 pairs, or homologs, of autosomes) 2 sex chromosomes

Question 48

Clinical features: Increased height, long extremities, low upper/lower segment ratio, gynecomastia, reduced facial and body hair (female hair distribution), delayed and incomplete puberty, small testes (testicular atrophy), infertility, developmental delay (learning disabilities, delayed speech and language development), increased risk for breast cancer.

Answer 48

Klinefelter Syndrome

Question 49

Karyotype: 47, XX or XY, +21

Answer 49

Trisomy 21

Question 50

DNA is wound around histone proteins to form a

Answer 50

nucleosome

Question 51

segment moves to another chromosome

Answer 51

translocation

Question 52

Passed from parent to child through the egg and the sperm

Answer 52

chromosomes

Question 53

5 STRUCTURAL ABNORMALITIES

Answer 53

* Deletions * Duplications * Translocations * Inversions * Substitution

Question 54

eyes slants up with palpebral fissures, enlarged tongue that sticks out of mouth, small stature & low muscle tone, gap between 1st & 2nd toe, broad hands with short fingers, epicanthic fold, low set of ears, low nasal bridge & dorsum, abnormal & excessive facial fat distribution, delayed growth of brain results in reduced mental capacity

Answer 54

trisomy 21

Question 55

happens when the segment of a chromosome is substituted with another segment to complete the structure

Answer 55

substitution

Question 56

1/500 to 1:1000 male births

Answer 56

Klinefelter Syndrome

Question 57

Clinical features: Low birth weight, microcephaly, micrognathia, low-set, malformed ears, clenched fists with overlapping fingers, congenital heart and renal abnormalities, rocker-bottom feet, severe intellectual disability, survival about one year.

Answer 57

Trisomy 18

Question 58

Karyotype: Typically 47, XXY (greater than 90%). However, other karyotypes have been described: 48, XXXY and 49, XXXXY and 46, XY/47, XXY (mosaicism)

Answer 58

Klinefelter Syndrome

Question 59

third most common autosomal trisomy

Answer 59

Trisomy 13

Question 60

chromatids are visible in

Answer 60

mitotic metaphase

Question 61

Structures that hold all of our genes

Answer 61

chromosomes

Question 62

Karyotype: 47, XX or XY, +13

Answer 62

Trisomy 13

Question 63

Most common sex chromosomal abnormality in females and the most common genetic cause of primary amenorrhea

Answer 63

Turner Syndrome

Question 64

Approximately 1 in 5000 to 1 in 16000 live births

Answer 64

Trisomy 13

Question 65

has low birth weight and a short life span for an individual

Answer 65

trisomy 18

Question 66

Clinical features: small or poorly developed eyes (anophthalmia or cyclopia), cleft lip and palate, congenital heart disease, cryptorchidism, brain or spinal cord abnormalities, weak muscle tone at birth

Answer 66

trisomy 13

Question 67

This technique is useful in finding out any chromosomal abnormalities such as extra or missing chromosomes

Answer 67

karyotyping

Question 68

DNA packing is facilitated by proteins called

Answer 68

histones

Question 69

Short stature, webbing of neck, low posterior hairline, broad chest and widely spaced nipples, cubitus valgus, pigmented nevi, coarctation or aorta, streak ovaries, infertility, amenorrhea, peripheral lymphedema at birth

Answer 69

Turner Syndrome

Question 70

types of chromosome based on the number of centromere present

Answer 70

1. Monocentric 2. Holocentric 3. Acentric 4. Dicentric

Question 71

Karyotype: 45, X accounts for 45% of cases because most zygotes cannot survive extrauterine life.

Answer 71

Turner Syndrome

Question 72

Terminal part of a chromosome

Answer 72

telomere

Question 73

It is an elongated segment that is sometimes present on a chromosome at the secondary constriction

Answer 73

satellite

Question 74

missing chromosome segment

Answer 74

deletion