week 2 Flashcards
what is direct communication between cells
contact dependent signalling
meaning they need to be in contact with each other when signalling.
what is indirect communication of cells
no direct contact between communicating cells
what are the five main types of indirect cell to cell communication and give an eg of each
1) endocrine, thyroid gland
2) neurocrine, hypothalamus
3) paracrine, interstitial fluid acts on a different cell
4) autocrine, interstitial fluid acts on the same cell
5) neurotransmitter, act on target cells
describe endocrine communication
- gland that produces hormone
- hormone released will enter through the blood stream to reach a target cell.
describe neuroendocrine communication
- produces a neurohormone
- hormone will go into the bloodstream and reach the target cell.
describe a paracrine cell
releases a paracrine molecule
- this will act on a target cell that is nearby
describe autocrine communication
- produces autocrine molecule
- creates an immune cell which is released to fight an infection
describe neurotransmission communication
starts with a neutron with a messenger called a neurotransmitter these react on both glands and small muscle cell.
what are the four differences between euro transmission and neuro secretion
- mediator molecules/ messengers:
neurotransmission= neuro transmitter
neurosecretion= neurohormones
- types of transport to target cells:
- neurotransmission= synapses
- neuro secretion= blood
- time to onset of action :
- neurotransmission= typically within milliseconds
- neuro secretion= seconds to hours
- duration of action:
- neurotransmission= generally briefer
- neuro secretion= generally longer
what are the 6 roles hormones regulate in the body
1- chemical composition
2- metabolism and energy balance
3- contraction of muscle cells
4- immune system response
5- control of growth and development
6- regulation of reproductive systems
what are the two main types of hormones
1- water soluble hormones
2- lipid soluble hormones
what are water soluble hormones an give an eg
hormones can travel into a watery liquid
eg insulin
what are lipid soluble hormone and give an eg
cannot travel through watery liquids however travel through structure
thyroid hormone
what does synergistic mean
enhances action of another hormone
what does antagonistic mean
oppose action of another hormone
what is DNA and its structure ( x6)
- compromises all the instructions for making all of the proteins that our body is going to need
- consists of a double helix made up of a sugar phosphate backbone
- dna is compromised of four different bases thymine, guanine, adenosine, cytosine
- adenine always pairs with thymine ( apple tree)
- cytosine always pairs with guanine ( car to garage)
- x shape so when going under cell division all dna is condensed and forms a chromosome
describe a gene
unit of heredity
specific location on a chromosome
what is an enzyme
type of protein that speeds up chemical reactions
what is an allele and give an eg
specific DNA sequence that we have got for a particular gene at a specific location
eg
- DNA sequence for brown eye colour pigment will be different than blue eye pigment sequence
what is a genotype give an eg
two alleles for a gene
Bb, BB
what is a phenotype
the outcome of the physical expressions of the protein due to the allele
what is cell division and what are the two types
process by which cells reproduce themselves
- mitosis
- meiosis
what is mitosis
replaces body cells/ sex cells
what is meiosis
from gametes in ovaries and testes
what is DNA replication
before any cell division occurs DNA must be replicated
replication of DNA occurs during the S phase of the cell cycle
what are the 6 phases of mitosis
- prophase
- pro metaphase
- metaphase
- anaphase
- telophase
- cytokinesis
describe prophase ( x3)
- chromosomes condense and become visible
- nuclear envelope breaks down
- centrosome move toward opposite poles
describe pro metaphase ( x3)
- chromosomes continue to condense
- kinetochores appear at the centrosomes
- mitotic spindle microtubules attach to kinetochores
describe metaphase ( x2)
- chromosomes are lined up at the metaphase phase
- each sister chromatid is attached to a spindle fibre originating from opposite poles
describe anaphase ( x3)
- centromeres split in two
- sister chromatids are pulled toward opposite poles
- contain spindle fibres being to elongate the cell
describe telophase ( x4)
- chromosomes arrive at opposite poles and begin to decondense
- nuclear envelope surrounds each set of chromosomes
- the mitotic spindle breaks down
- spindle fibres continue to push poles apart
describe cytokinesis ( x2)
- animal cells: a cleavage furrow seperates the daughter cells
- plant cells: a cell plate, the precursor to a new cell wall.
describe meiosis
- two rounds of cell division
- the first division halves the chromosome number
describe prophase 1 of meiosis
- the chromosomes condense and the nuclear envelope breaks down. crossing over occurs.
describe metaphase 1 of meiosis
pairs of homologous chromosomes move to the equator of the cell
describe anaphase 1 of meiosis
homologous chromosomes move to the opposite poles of the cell
describe telophase and cytokenesis 1 of meiosis
chromosomes gather at the poles of the cells, the cytoplasm divides
describe prophase 2 of meiosis
a new spindle fibre forms around the chromosomes
describe metaphase 2 of meiosis
chromosomes line up at the equator
describe anaphase 2 of meiosis
centromeres divide chromatids move to the opposite poles of the cell
telophase and cytogenesis 2 of meiosis
a nuclear envelope forms around each set of chromosomes the cytoplasm.
mitosis vs meiosis ( number of chromosomes, number of daughter cells, genetically identical?, functions)
number of chromosomes= \
mitosis= 46
meiosis= 23
number of daughter cells
mitosis= 2
meiosis= 4
genetically identical:
mitosis= yes
meiosis= no
function:
mitosis= grow tissues, replaces body cells
meiosis= provide gametes
what is transcription
moving DNA to becomce m RNA copy of the message
what is translation
mRNA copy to a specific protein made at ribosomes
what is mutation
- change in the DNA sequence for a gene to a new allele
what are the outcome of mutation ( x3)
- still produce functional protein
- produce protein that does not work as well
- no longer produces functional protein or produce an insufficient amount
what is co dominance
two alleles are dominant over a recessive allele
