Lecture 13 Flashcards Preview

Biology > Lecture 13 > Flashcards

Flashcards in Lecture 13 Deck (24):
1

asexual reproduction

The generation of offspring from a single parent that occurs without the fusion of gametes (by budding, division of a single cell, of division of the entire organism into two or more parts). In most cases, the offspring are genetically identical to the parent.

2

autosome

A chromosome that is
not directly involved in determining sex; not
a sex chromosome.

3

chiasmata

The X-shaped, microscopically
visible region where crossing over has
occurred earlier in prophase I between homologous
nonsister chromatids. Chiasmata
become visible after synapsis ends, with the
two homologs remaining associated due to
sister chromatid cohesion.

4

crossing over

The reciprocal exchange of genetic
material between nonsister chromatids
during prophase I of meiosis.

5

diploid cell

A cell containing two
sets of chromosomes (2n), one set inherited
from each parent.

6

fertilization

The union of haploid gametes
to produce a diploid zygote.

7

gamete

Sex Cell

8

gene

A Section of DNA

9

haploid cell

Cell containing one set of chromosomes

10

heredity

The transmission of traits from one
generation to the next.

11

homologous chromosome

A pair of chromosomes of the same
length, centromere position, and staining
pattern that possess genes for the same
characters at corresponding loci. One homologous
chromosome is inherited from
the organism?s father, the other from the
mother. Also called homologs, or a homologous
pair.

12

karyotype

A display of the
chromosome pairs of a cell arranged by size
and shape.

13

life cycle

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

14

locus

A specific
place along the length of a chromosome
where a given gene is located.

15

meiosis

A modified type of cell
division in sexually reproducing organisms
consisting of two rounds of cell division
but only one round of DNA replication. It
results in cells with half the number of chromosome
sets as the original cell.

16

meiosis I

The first division of a two-stage process
of cell division in sexually reproducing
organisms that results in cells with half the
number of chromosome sets as the original
cell.

17

meiosis II

The second division of a two-stage
process of cell division in sexually reproducing
organisms that results in cells with
half the number of chromosome sets as the
original cell.

18

recombinant chromosomes

crossing over produces recombinant chromosomes which combine genes inherited from each parent

19

sex chromosomes

x and y chromosome. Determines gender

20

sexual reproduction

A type of reproduction
in which two parents give rise to offspring
that have unique combinations of genes inherited
from both parents via the gametes.

21

somatic cell

Any cell in a multicellular
organism except a sperm or egg or
their precursors.

22

tetrad

A protein holds homologous chromosomes together tightly
Now they are called a tetrad

23

variation

Differences between members of
the same species.

24

zygote

The diploid cell produced by
the union of haploid gametes during fertilization;
a fertilized egg.