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Flashcards in Chromosomes And Meiosis Deck (30)
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1

Chromosomes

Long, thread-like structures that form part of the chromatin network in the nuclei of cells
- can be stained easily

2

Somatic cells

Body cells

3

Homologous pair

Matching maternal and paternal chromosomes (same size, shape and coding genes in place)

4

Chromatids

2 identical threads formed during chromosome replication

5

Diploid

2n
Cells containing full number of chromosome (e.g. 46 in humans)

6

Allele

One or two more forms of a gene
- a contrasting form of a gene for the same characteristic

7

Meiosis

Cell division that takes place in reproductive organs of both plants and animals to produce gametes (sex cells) in animals and spores in plants

8

Haploid

n
Cells that have half the number of chromosomes

9

Gene

A short length of DNA which controls and organisms characteristic
- sections of chromosome that code for specific characteristics

10

Morula

Basic mass of replicated cells which form basic embryo

11

Microsporangia

Pollen sacs in the male anthers (part of stamen)

12

Mega sporangia

Ovules in the female ovaries

13

Meiosis 1

Reduction division
- results in two cells being formed- each with a haploid (n) number

14

Meiosis 2

Copying division
- involves two haploid cells replicating to form 4 haploid cells

15

Chiasma

Point of contact and where breakage occurs between two chromatids

16

Synapsis

Process in which replicated homologous pairs come together to form bivalents

17

Bivalent

Chromosomes which lie next to each other

18

Tetrad

2 chromosomes that make up a homologous pair

19

Genome

All the genes in an organism

20

Chromosomal non-disjunction

Occurs when chromosomes fail to separate correctly during Anaphase 1 of meiosis

21

Aneuploidy

Condition resulting from fertilization involving abnormal gametes which result in a zygote with an extra/ missing chromosome

22

Syndrome

Physical/ mental characteristics affected individuals suffer from

23

Diagnosis

Identifying the nature of an event

24

Prognosis

Predicting how the event will develop

25

Amniocentesis

Process whereby a small sample of fluid is removed from the amniotic cavity in the uterus

26

Polyploidy

A condition where there are more than two sets of chromosomes in a cell.
Occurs more commonly in plants
Occurs as a result of abnormal mitosis where a full set of chromosomes does not separate during Anaphase 1

27

Total non-disjunction

The phenomenon there a full set of chromosomes does not separate during meiosis

28

Autosome

The normal chromosomes not involved in sex determination

29

Gonosome

The sex chromosomes that determine the gender of an individual

30

Karyotype

The complete number of chromosomes in a diploid cell, arranged in Paris according to size, shape and number