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Flashcards in Chapter 13 Deck (43)
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1

Living organisms are distinguished by their ability to ...

reproducing offspring that resemble their parents but may look slightly different (demonstrating variation)

2

Variation

shows that offspring differ somewhat in appearance from parents and siblings

3

Genetics

the study of heredity and hereditary variation (uniqueness)

4

Offspring acquire genes from parents by...

inheriting gene on chromosomes

5

Genes

the units of heredity and are composed of segments of DNA

6

Each gene in an organism's DNA has a ...

specific locus (location) on a certain chromosome

7

In sexual reproduction,
in terms of genes

we inherit one set of chromosomes from our mother and one set from our father

8

In asexual reproduction,

one parent produces genetically identical or exact copy (clone) offspring by mitosis
- more simple process

i.e. the multicellular hydra reproduces by budding

9

In sexual reproduction,

2 parents (produce gametes) give rise to offspring that have unique combinations of genes inherited from the two parents

10

Fertilization and meiosis alternate in...

sexual life cycles

11

Life Cycle

is the generation-to-generation sequence of stages in the reproductive history of an organism

12

in humans, each somatic cell has...

46 chromosomes
made up of 2 sets, one from each parent

13

Karyotype

an ordered, arranged, visual representation of the chromosomes in a cell that can be used to determine their homology or similarity

14

Homologous chromosomes (autosomes)

a pair of chromosomes that have the same characteristics

humans have 22 autosome pairs

15

Heredity

the transmission of genes on chromosomes and their traits from one generation to the next

16

Sex Chromosomes

distinct from each other and are represented as X and Y

determine the "sex" of an individual
XX = female
XY = male

17

Diploid Cell

has 2 sets of each of its chromosomes and a human has 46 chromosomes (2n=46)

where n = the number of single set chromosomes

18

n =

the number of single set chromosomes

19

Haploid

sperm and ova (gametes)

have only one set of chromosomes

20

In a cell in which DNA synthesis has occurred...

the chromosomes are duplicated and consist of 2 identical sister chromatids

21

Gametes

unlike somatic cells, gametes only contain 1 set of chromosomes

22

Meiosis

variety and the production of new cells that are genetically distinct

cells produce non-identical daughter cells that are used in reproduction
cells contain genes

at sexual maturity, the ovaries and testes produce haploid gametes by this process

23

Forming a Diploid Zygote

during fertilization, the gametes, sperm, and ovum fuse forming a diploid zygote that develops into an adult organism

24

3 main types of sexual cycles differ in the ...

timing of meiosis and fertilization

25

In animals,

meiosis occurs during gamete formation and the gametes are the only haploid cells

26

plants and some algae exhibit...

an alternation of generations where the life cycle includes both diploid (sporophyte) and haploid (gametophyte) multicellular stages

27

in most fungi and some protists, meiosis produces

haploid cells that gives rise to a haploid multicellular adult organism that carries out mitosis, producing cells that will become gametes

28

haploid multicellular organism

predominant phase in plants

29

diploid multicellular organism

predominant phase in animals/humans

30

Meiosis

resembles mitosis but reduces the number of chromosome sets from diploid to haploid

takes place in 2 sets of divisions