lecture 11 Flashcards
How long is the DNA’s length
6 ft
What sections is the DNA library divided into
chromosomes
What are the 4 bases of DNA
- Adenine
-Thymine
-Cytosine
-Guanine
What are genes a recipe for
proteins
What is the cell membrane composed of
proteins and phospholipids
Where does Transcription occur
In the nucleus, copies DNA
Where does Translation occur
outside the nucleus in the cytoplasm
How many chromosomes do we have ?
46 chromosomes
What are chromosomes
pieces of DNA
How are chromosomes made
when DNA is cut, it recoils into chromosomes
what is a protein made up of
a sequence of amino acids
How is a protein made
a gene in the DNA library is transcribed to make a copy of the gene (aka the mRNA)
mRNA leaves nucleus so that ribosomes can translate the mRNA into amino acids to make the protein structure
The 4 properties of DNA
-replicate itself
-store information
-direct synthesis
-mutate
What is DNA replication
the process of copying all of the cells genes to make a duplicate of the DNA library
During replication what gets fully replicated and what doesnt
centromere gets fully replicated
telomeres do no fully replicate
what is a telomere
the tips of the chromosome
what is a centromere
the center of the chromosome
are sex hormones proteins
no
What happens to telomeres as they continue to duplicate
the telomere gets shorter and shorter
What happens when a telomere is too short
the cell stops dividing and eventually dies
the shorter the telomere the more aging seen
undifferentiated cells
no specific function, their telomeres never shorten so there no limit to cell division
cancerous cells mixed with normal ones
differentiated cells
cannot keep their telomere at its original length, eventually reaches their limit for cell division and dies.
aggressive cancerous cells
what part of the cell cycle does cell division occur in
M-phase (cell splits in two parts )
What is Mitosis
the division of 1 nucleus into 2 nuclei
What is cytokinesis
splitting a cell with 2 nuclei into 2 separate daughter cells
What are the 4 steps of Mitosis
- Prophase
- Metaphase
- Anaphase
- Telophase
What occurs in Prophase
remember chromosomes are in the middle
centrioles double and move to opposite ends of nucleus
centrioles form spindle fibers that attach to the nuclear membrane
spindle fibers pull apart and nucleus disappears
spindle fibers attach themselves to the exposed chromosomes
What occurs in Metaphase
spindle fibers continue pulling exposed chromosomes
chromosomes align
What occurs in Anaphase
centromeres of all chromosomes replicate causing the chromosome to split in half
spindle fibers keep pulling, causing separated daughter cells to gather at opposite parts of the cell
What occurs in Telophase
Spindle fibers disappear
New nuclear membrane reforms around each new set of daughter chromosomes at opposite poles of the cell
1 cell with 2 nuclei
What occurs during cytokenesis
Occurs right after telophase
Cytoplasmic membrane starts to pinch opposite sides to separate the 2 nuclei until they become 2 complete daughter cells
what is interphase
the resting phase
What is the epidermis
the top layer of the skin
What is the top layer of the epidermis called
Stratum corneum, which is composed of dead epithelial cells filled with Keratin
What is the Dermis
2nd layer, aka the active layer of skin containing :
-blood vessels
-nerve endings
-hair follicle
-oil glands
-sweat glands
What is the Hypodermis
3rd layer, composed of areolar or adipose tissue connecting the skin to the muscle
What are the functions of the skin
-protect organism from microbes and dehydration
-body temp regulation
-collection of sensory information
-production of vitamin d
-excretion of electrolytes
-absorption of some fat-soluble substances
What are Decubitus Ulcers
Pressure sores, or bed sores
develop when pressure is applied to a part of the body for a long period of time
How many stages are there in bed sores
4 & it depends on the number of tissue layers affected
Stage 1 of bed sores
only the epidermis is involved
Stage 2 of bed sores
epidermis & dermis disintegrated
stage 3 of bed sores
involves the pink muscle at the bottom of the ulcer
Stage 4 of bed sores
involves all layers of tissue all the way to the bone
