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
how are muscle cells special?
- has fibres that can contract and relax which allows us to move them
- contains many ribosome since protein is essential for muscle function
how are goblet cells special?
- long and tube like which is good for sucking up nutrients
- secrete a lot of mucus
how are xylem cells special?
- in plant cells
- a continuous hollow tube which helps to transport nutrients from the roots up
how are palisade mesophyll cells special?
- in plant cells
- lots of chloroplasts to carry out photosynthesis
- packed very tightly to the upper layers of leaves to maximize sugar production
how are epidermal cells special?
- in plant cells
- outer cells of plants that creates barrier from outside world
- dna is structured differently depending on location
how are spongy mesophyll cells special?
- in plant cells
- located on bottom of plant leaves, contain less chloroplasts that palisade mesophyll cells since there’s not as much sun
- loosely packed to allow exchange of oxygen and co2 for photosynthesis
how are guard cells special?
- in plant cells
- underside of leaf, usually in a pair
- has large vacuoles that fill up with water during daytime to open stoma for gas exchange for photosynthesis, removes water to close stoma for the night
how are phloem cells special?
- in plant cells
- transports nutrients down during summer/fall for storage, transports nutrients up in spring to start photosynthesis
- has no nucleus to maximize space to carry nutrients
how are storage cells special?
- in plant cells
- stores starch
- has specialized organelle called amyloplasts that are able to store starch for a long time
shortest phase of the cell cycle?
anaphase
how do cells become specialized?
stem cells activate different genes and become specialized, cannot turn back
what is a stem cell
- “blank slate” that can be turned into any other cell
- found in all multicellular organisms
- can renew themselves
what are the 3 types of basic stem cells
embryonic stem cells (totipotent), adult stem cells (pluripotent) and induced pluripotent stem cells (originally multipotent)
what are totipotent stem cells?
stem cells able to become any other cell type or become a completely new embryo
what are pluripotent stem cells?
- stem cells able to turn into any cell found in an adult
what are multipotent stem cells?
- stem cells able to turn into any cell within a certain group (hematopoietic stem cells are found in bone marrow, can only turn into different types of blood cells)
where can somatic stem cells be found in the body
brain, teeth, liver, gut, skin, heart, bone marrow etc.
what can somatic stem cells be used for? what are some considerations?
- can treat blood related diseases by producing red blood cells
- difficult to isolate
- would need immunosuppressant drugs to be transplanted
how does isolating embryonic stem cells work?
- sperm and egg cell join
- embryo develops (5-7 days)
- remove inner cell mass from blastocyst
- grow in dish
- stimulate cells to change into variety of cell types
what can isolating embryonic stem cells lead to? considerations?
- since they can become any cell in body, could treat many diseases
- would need immunosuppressant drugs to be transplanted
what are somatic stem cells?
stem cells that exist naturally in body involved in growth, healing, replacing
what are embryonic stem cells?
formed as a natural part of development (when sperm fertilizes egg)
what are induced pluripotent cells?
created by “reprogramming” cells that produce connective tissue(multipotent) back into a pluripotent state.
how do you create induced pluripotent stem cells?
- isolate cells from patient (ex skin cells)
- “reprogram” cells
- wait a few weeks
- you have pluripotent stem cells
- stimulate cells to help them differentiate into a variety of cell types
what are the potentials of induced pluripotent stem cells? any considerations?
- able to become any cell in body, could treat many disease
- body will not reject these cells
- cheaper than embryonic stem cells
- could result in genetic mutations
how do you create embryonic stem cells through therapeutic cloning?
- isolate cells from body, remove nucleus
- isolate egg cell, remove nucleus
- put nucleus of body cell into egg cell
- reprogram dna that’s inside the nucleus
- stimulate cell division
- isolate inner cell mass from blastocyst and grow in a dish
what are the potentials of creating ES cells from therapeutic cloning? considerations?
- can become any cell in body
- costly, inefficient
- involves cloning of humans
how do you create embryonic stem cells through reproductive cloning?
- isolate cell from body, remove nucleus
- isolate egg cell, remove nucleus
- put nucleus from body cell into egg cell
- reprogram dna
- stimulate division until egg reaches blastocyst stage
- insert blastocyst into surrogate to develop
what is the potential of creating ES cells through reproductive cloning? considerations?
- creates embryonic stem cells that can grow a new organism
- an exact clone will be created
- clone may not be as healthy as original
who was henrietta lacks?
african-american woman born in 1920 who houses the HeLa cells
what medical breakthroughs were the HeLa cells able to achieve?
- developed polio vaccine
- drugs to help parkinson’s disease
- treatment for leukaemia(chemotherapy)
- gene mapping
- HIV vaccine
- cloning
- IVF
what are ethic violations that happened in henrietta lacks’s story?
- doctors took sample of her tissue and experimented without her consent
- family wasn’t informed about her contributions until 25 years later
why are HeLa cells so unique?
- “immortal cells”, the cells never died
- cells kept on regenerating at an extraordinary rate
- HeLa cells don’t show any signs of aging
what is biotechnology?
using living organisms to make useful chemicals, products, or perform a task
how does natural plant cloning work?
- asexual reproduction
- ex. spider plants grow plantlets on stem to produce new spider plants
- ex. potatoes produce tubers which can grow new roots and shoots
how does artificial plant cloning work?
using plant tissue cultures or making cuttings
what is selective breeding (traditional breeding)?
- crossbreeding plants that had wanted characteristics to create better plants
- characteristics came from random mutation
- corn came from teosinte plant that had been selectively bred for many years
what is mutagenesis (mutation breeding)?
- breeders wanted more diversity
- expose seeds to chemicals or gamma irradiation to change plant dna to give them better characteristics
- ex. bananas, peanuts, peppermint came from mutagenesis
what are transgenic organisms?
- organisms that contain dna from two different species that have been put together
- also known as GMOs
- ex. many corn varieties are transgenic organisms
what are the benefits of transgenic organisms?
- keeps organism resistant to pests
- increase of nutrient content
- resistance to herbicides
what is genetic editing (CRISPR)?
- technology that can be used to edit genes
- CRISPR can be used to disable or fix faulty genes
why is CRISPR an important discovery?
- allows scientists to rewrite the genes of any organism with precision
what is artificial insemination?
putting the sperm of a male into reproductive system of a female
what is in vitro fertilization?
- when egg and sperm cell are put in a petri dish, fertilized, then embryo gets implanted in uterus of a female
- many embryos are implanted because of low success rate
- $22000 in canada
what are some ethical considerations when dealing with biotechnology?
- making a mistake could cost the life of a living organism
- incorrectly modifying a gene could result in harmful/painful modifications
what are tissues?
groups of specialized cells that function together to perform special tasks
what are the four animal tissues?
epithelial, connective, muscle, nervous
what are the four plant tissues?
ground, vascular, dermal, meristematic
importance of animal epithelial tissue
protection, secretion, absorption, cleaning, to reduce friction between blood vessels
examples of animal epithelial tissue
skin, lining of mouth/nose, lining of digestive system
importance of animal connective tissue
- to join other tissues together
examples of animal connective tissue
tendons, ligaments, bones, blood, adipose(fat), collagen
importance of animal muscle tissue
allows physical activities to be performed
what are the 3 types of muscle tissue? are they involuntary or voluntary?
- cardiac muscle cells, involuntary
- skeletal muscle cells, voluntary
- smooth muscle cells, involuntary
where are cardiac muscle cells found in body?
heart
where are skeletal muscle cells found in the body?
throughout entire body (ex. tongue, arms, legs)
where are smooth muscle cells found in the body?
digestive system, guts, lungs, walls of all internal organs except the heart
importance of animal nervous tissue
to create impulses and transmit signals through the body
where is nervous tissue located?
brain, spinal cord, nerves
what is an organ
- organized group of tissue that perform a specific task
- many organs include all types of tissue which work together to allow organ to function
how do all the types of tissues work together to allow skin to function?
epithelial: the protective layer
connective tissue: provides support and strength to skin
nervous tissue: allows for perception of touch, pain
muscle tissues: contract to make hairs stand up
what is the integumentary organ system?
the body’s outer layer (ex. skin, hair, nails, glands)
what is the endocrine organ system?
made up of the body’s hormones (ex. pancreas, thymus, thyroid)
what is the lymphatic organ system?
group of organs/tissues/vessels that protect body from infection and keep healthy balance of fluid throughout body (ex. bone marrow, thymus, lymph nodes)
importance of plant meristomatic tissue, where is it found?
allows plants to create new cells to grow, found in root tips, buds, stems
- meristematic cells can differentiate to form specialized cells (like stem cells)
importance of plant dermal tissue, where is it found?
- protects structures within the plant
- allows water and gases to be exchanged
- found on outer layer of plant
importance of plant ground tissue, where is it found?
- found everywhere in plant and forms most of plant
- function varies depending on location
roots: store food +water
leaves: perform photosynthesis
stems: provide strength, support
importance of plant vascular tissue, where is it found?
- transports materials through plant
- includes xylem which transports nutrients up, and phloem which can transfer nutrients both ways
what is the importance of leaves, stem, root, and flowers of a plant?
leaves: to perform photosynthesis
stem: to support and transport
roots: to store, absorb nutrients
flowers: for seed production
what are the organ systems within a plant?
- roots - water/nutrient absorption, storage
- shoots - photosynthesis, reproduction, support
how does the surface area of a cell affect its ability to transport materials?
larger surface area = more amount of space that’s able to be used to transport materials
