The Chromosomal Basis of Heredity (A)-ppt Flashcards
(78 cards)
1
Q
- it is the series of events that take place in a cell leading to its replication
A
the cell cycle
2
Q
types of cells:
A
a. prokaryotic
b. eukaryotic
3
Q
- unicellular
- lack a defined nucleus
- e.g. monerans, bacteria, cyanobacteria
A
prokaryotic
4
Q
- multicellular
- have a defined nucleus
- e.g. plant, animal, protist, fungi
A
eukaryotic
5
Q
________ is the method by which prokaryotes produce new individuals that are genetically identical to the parent organism.
A
Binary fission
6
Q
Eukaryotes have two major
types of cell division:
A
a. mitosis
b. meiosis
7
Q
- is used to produce new body cells for growth and healing
A
Mitosis
8
Q
- is used to produce sex cells (eggs and sperm)
A
meiosis
9
Q
Depending on cell type, typical eukaryotic cells have a cell
cycle of ______ hours, which is divided into phases.
A
16 to 24
10
Q
DNA means
A
Deoxyribonucleic acid
11
Q
- is a molecule that carries genetic information in living organisms. It looks like a twisted ladder (double helix) and is found
inside the nucleus of our cells.
A
DNA
12
Q
- the basic physical unit of heredity and it is passed on from generation to generation in cells
A
gene
13
Q
- determines the characteristics of the individuals
produced.
A
gene
14
Q
the entirety of genes or genetic material that is present in a cell or organism
A
genome
15
Q
A ________ contains all of the information needed to build and make an organism function.
A
genome
16
Q
are thread-like structures present in the nucleus, which carries genetic information from one generation
to another.
A
chromosome
17
Q
Chromosome means: chroma – ______; some - ____, that refers to its staining ability by certain dyes
A
colour; body
18
Q
_______ in 1842, first observed the rod-like structure present in the nucleus of the plant cell.
A
Karl Nägeli
19
Q
It is clearly visible only when the cell is undergoing division.
A
chromosome
20
Q
At ______, chromosomes are visible as thin chromatin fibres present in the nucleoplasm.
A
interphase
21
Q
During cell division, the chromatin fibres condense and _________ are visible with distinct features.
A
chromosome
22
Q
Chromosome Structure:
A
a. chromatids
b. telomere
c. centromere
23
Q
- one of the longitudinal subunits of a replicated chromosome joined to its sister chromatid at the centromere
A
chromatids
24
Q
- a region of repetitive DNA at the end of chromosomes, which protects the end of the chromosome from destruction
A
telomere
25
- the point at which two parts chromatids of a chromosome join and at which the spindle fibers are attached during cell division
centromere
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Types of Chromosomes based on the position of the centromere:
a. metacentric
b. sub-metacentric
c. acrocentric
d. telocentric
27
- centromere in middle forming two equal arms
metacentric
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- centromere placed near to one end resulting in one shorter and one long arm
sub-metacentric
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- centromere placed close to one end forming one extreme short and one extreme long arm
acrocentric
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- terminally placed centromere
telocentric
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It is the growth cycle of an individual cell consisting of the following phases:
Interphase & Mitotic Phase.
- produce identical cell
cell division
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phases of cell cycle:
a. interphase
b. mitotic phase
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- The period between mitotic
divisions - that is, G1, S and G2
- non-dividing phase
interphase
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Metabolic changes prepare the cell
for division.
G1 Phase
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The cell increases in volume
(nucleus & cytoplasm are enlarging
toward mature size) by imbibing
water & nutrients & building new
protoplasm
G1 Phase
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Cytoplasmic organelles are formed,
e.g., endoplasmic reticulum, golgi
apparatus, ribosomes,
mitochondria, & chloroplast
G1 Phase
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DNA synthesis replicates the
genetic material.
S Phase
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Each chromosome now consists of
two sister chromatids.
S Phase
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There is active synthesis of RNA &
proteins necessary for
chromosome synthesis.
G2 Phase
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Mitotic spindles are also starting to
be formed.
G2 Phase
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Cell prepares itself for mitosis by
synthesizing needed components.
G2 Phase
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The process by which a cell
divides to form two new cells,
either to produce identical cells
(mitosis) or to produce cells with
half the number of chromosomes
(meiosis)
cell division
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Two types of cell division:
1. Mitosis
2.Meiosis
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- process of cell division by which one cell results in two daughter cells, each with a set of chromosomes identical to that of the parental cell.
mitosis
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mitosis is important for:
* replacement of worn out or damaged tissues
* repair of injuries,
* multicellular growth and development by
increasing the number of cells
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Mitotic division occurs in two parts:
a. karyokinesis
b. cytokinesis
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- (nuclear division) (having the
prophase, metaphase, anaphase, and telophase)
karyokinesis
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- (cytoplasmic division)
cytokinesis
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prophase:
a. early prophase
b. late prophase
50
* Chromosomes are condensed and
consist of 2 sister chromatids
* The nuclear membrane begins to break down and nucleoli start to disappear
* Spindle fibers appear
early prophase
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* The centromere joins each pair of sister
chromatids to the spindle fiber
* Nucleoli & nuclear membrane
completely disappears by late prophase
late prophase
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The spindle fibers grow and forms
attachments to the chromosomes on the opposite sides of the centromere
metaphase
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* The chromosomes line up along the middle of the cell (_____/equatorial plate)
metaphase
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The chromatids in each chromosome separate from each other except at the centromere
metaphase
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In plants, the centromeres and their accompanying centrioles are generally missing although spindles are nevertheless present
metaphase
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The centromeres become functionally double
anaphase
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Centromeres divide to create two chromosomes instead of a pair of attached chromatids
anaphase
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Spindle fibers shorten due to depolymerization, pulling the sister chromatids apart and
drawing them to the opposite poles of the cell. Once they have separated, they are
individual chromosomes.
anaphase
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Upon reaching the opposite poles, the chromosomes regroup into two nuclear structures
telophase
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nuclear envelopes reassemble and surround each set of daughter chromosomes while spindle fibers disassemble
telophase
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nucleoli reappear inside the newly formed nuclei
telophase
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chromosomes decondense in the daughter cells to become chromatin and the cells are once again in Interphase
telophase
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The chromosomes begin to uncoil & lengthen & finally lose their visible identity
telophase
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Usually follows mitosis or
begins during telophase.
cytokinesis
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In plant tissues, the cytoplasm
is divided via cell plate
formation where separation
starts from the inside of the
cell towards the periphery
cytokinesis
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The cytoplasm is divided
between the two cells forming
two daughter cells.
cytokinesis
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sequence of two cell division, each cell divides twice while the
chromosomes are duplicated only once, resulting gametes have
only half the chromosome number of the original cell
meiosis
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meiosis stages:
a. Meiosis I (reduction division); (PMAT)
b. Meiosis II (equational division);
(PMAT)
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one of a pair of chromosomes
with the same gene sequence,
loci, chromosomal length, and
centromere location
Homologous chromosome
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– pair of two homologous
chromosomes formed by synapsis
during the early stages of meiosis.
Bivalent
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– is the group of four sister
chromatids inside the homologous
chromosome pair
Tetrad
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A bivalent consists of ______ pair/pairs sister
chromatid/chromatids and ______ pair/pairs of
homologous chromosomes.
two; one
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the pairing of two chromosomes that occurs during meiosis
synapsis/ syzygy
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The exchange of corresponding parts between non-sister chromatids of homologous chromosomes producing a
new combinations is called
_______________
crossing over
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point of contact between two non-sister chromosomes belonging to the homologous chromosomes
chiasma
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are chromosomes other than the sex chromosomes. In humans, there are 22 pairs of _________.
autosomes
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– A specific variation of a gene. Example: Blue eyes, green eyes, type A blood, black skin,
white skin
allele
78
refers to the period of rest between meiotic divisions, similar to the interphase stage
in mitosis
interkinesis
