quiz 2 bio (2.6-2.12) Flashcards
what is a chromatin
- thin thread of dna like pile of spaghetti
- found in cell nucleus
- condenses to form chromosomes
what are chromosomes
- condensed chromatins (condensed dna)
what are chromatids
- half of a chromosome (when chromosome splits into two chromatids during cell division)
chromatin during cell division
when cells divide..
- chromatin condenses to form chromosomes
- chromosomes split into two chromatids
- chromatid becomes chromosome in their new cell
how many chromosomes do humans have
46 in total, 23 pairs
diploid definition
containing two complete sets of chromosomes, each parent contributing one chromosome to the pair. result of sexual reproduction
haploid definition
having half of 23 pairs of chromosomes (ex. egg cell or sperm cell)
zygote definition
-a fertilized egg
- is a diploid
longest phase of cell cycle?
interphase (around 80%)
stages of mitosis?
prophase, metaphase, anaphase, telophase
what happens during prophase?
- nuclear membrane disappears
- nucleolus disappears
- spindle fibres grow out of centrioles, attach to centromeres
- centrioles move to opposite sides of cell
- chromosomes get thicker
sister chromatids definition
duplicated chromosomes attached with a centremere
centromere definition
part where sister chromatids join
what happens during metaphase?
- spindle fibres pull chromosomes to middle of cell
- checks that chromosomes are in a line and attached to spindle fibres
what happens during anaphase?
- centromeres separate and daughter chromosomes are pulled to centrioles by spindle fibres
daughter chromosome definition
when sister chromatids separate and become individual structures (during anaphase)
what happens during telophase?
- nuclear membrane forms again
- nucleolus reappears
- daughter chromosomes become chromatin
what happens during cytokinesis?
- occurs right after mitosis
- cell membrane pinches together and forms two identical daughter cells
how does mitosis + cytokinesis in plant cells work
- plants lack centrioles but still have spindle fibres
- vesicles from golgi bodies fuse in the middle of cell to form a cell plate which has materials to create a cell wall and separate daughter cells
what is cancer
uncontrolled growth of abnormal cells
what is the branch of medicine dedicated to cancer called
oncology
how are cancer cells different from normal cells?
- cells don’t listen to apoptosis signals, keep dividing
- cancer cells grow to rapidly to have a specialized function
- cannot be identified by immune system as abnormal
what is a tumour suppressor gene
- prevent uncontrolled cell growth
- faulty tumor suppressor genes can lead to cancer and tumours
what are hereditary mutations
- cell mutations passed down from parents
- mutation is present in all cell of body for whole life
what are acquired mutations?
- mutation develops during one’s life
- can only occur in stomatic cells
- mutation cannot be passed onto offspring
- can occur because of environmental factors (ex. uv rays)
what is a carcinogen?
substances that increase risk of cancer (ex. asbestos, alcohol, uv rays, processed meat)
what is a de novo mutation?
- mutation that occurs during dna mutation as offspring is created
- hard to figure out why these happen
characteristics of benign tumours
- typically not cancerous
- doesn’t invade nearby tissues or spread
- grows slowly
- usually doesn’t reappear
- has smooth regular shape
characteristics of malignant tumours
- cancerous
- may invade nearby tissue and spread
- grows quickly
- more likely to reappear
- uneven shape
define angiogenesis
- process of new blood cells forming from pre-existing blood cells
- occurs during cancer as cancer manipulates body to develop new blood vessels to keep cancer alive
define metastasis
- development of secondary malignant growth
- when cancer spread from origin to other parts of the body
pros and cons of ultrasounds
pros: captures images in real time, allows different views of tumours
cons: cannot determine if tumour is cancerous or not
pros and cons of chemotherapy
pros: kills cancer cells that have spread to other parts of the body
cons: kills healthy cells during process of killing cancer cells
pros and cons of endoscopies
pros: leaves no scar, minimizes cutting of healthy tissues/muscles
cons: can be uncomfortable for people with sensitive gag reflex
pros and cons of radiation
pros: highly effective at killing cancer cells
cons: bad side effects, damages healthy cells, only used on isolated cancers
pros and cons of MRIs
pros: precisely pinpoints cancer cells
cons: magnetic field can affect body, claustrophobia
pros and cons of surgery for tumours/cancer
pros: can remove tumours causing pain
cons: only used on isolated cancers, can increase risk of infection
pros and cons of biopsies
pros: can be used to determine type of cancer
cons: risk of haemorrhage
pros and cons of ct scans
pros: allows doctors to determine size, location of cancer
cons: tumours can be overlooked
pros and cons of x-rays
pros: can detect cancer in bones, organs
cons: 2D image rather than 3D
how are white blood cells special?
- contains a lot of lysosomes to kill unwanted organisms
- has finger-like extensions to grab organisms and destroy them
how are sperm cells special?
- pointy head to penetrate egg cell
- long flagellum(tail) to propel forwards
- has a lot of mitochondria since it needs a lot of energy to move
how are skin cells special?
- deep skin cells are round, square-like or elongated
- stack on top of eachother to form protective layer
how are red blood cells special?
- contains hemoglobin that makes cell turn red when oxygen is absorbed
- disc shape to maximize surface area for oxygen carrying
- flexible to fit through small spaces
- no nucleus to maximize space for oxygen
how are fat cells special?
- like a cushion for organs
- contains a large vacuole so that it can store fat
- vacuole pushes nucleus to the outer edge
how are nerve cells special?
- star shaped cell body (dendrites) to make connections and receive messages
- long, thick extension (axon) that carries information to other cells
- not regenerated during lifetime
- thin and long which allows signals to be transported quickly
how are bone cells special?
- densely packed
- grow in multi layered columns like growth rings of a tree
- blood vessel in each column