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104 Cards in this Set
- Front
- Back
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What is the 4 main types of tissue? |
Epithelial (lining) tissue Connective tissue e.g. blood bone and cartilage- they hold structures together. Muscle tissue- made of cells that are specialised to contract and cause movement. Nervous tissue- made of cells specialised to conduct electrical impulses. |
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What is the epithelial tissue and what is it's characteristics? |
covers and lines free surfaces of the body e.g. skin and cavities of the digestive and respiratory systems. Epithelial tissue is almost entirely made up of cells which are v close together and form continuous sheets. adjacent cells are bound together by lateral contacts e.g. tight junctions -no blood vessels- cells receive nutrients from tissue fluid in connective tissue -short cell cycles to replace damaged cells - specialised to carry out a function e.g. protect,absorb,filtrate etc. |
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What is a connective tissue? give examples of it |
It's widely distributed in the body.consists of non-living extra-cellular matrix containing proteins (collagen and elastin) and polysaccharides (e.g. hyaluronic acid) This matrix separates living cells within the tissue an enables it to withstand forces e.g. weight. Blood bone and cartilage tendons and ligaments are all examples of connective tissue. skin is also an example. |
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What makes up cartilage? What are the 3 types? Where are they found? |
immature cartilage cells are called chondroplasts they divide by mitosis and secrete extra-cellular matrix once this has been synthesised chondroplasts become mature and less active chondocytes which maintains the matrix. Hyaline cartilage- forms embryonic skeleton and joins long bones or ribs to sternum. found in nose and Larynx Fibrous Cartilage- disks between vertebrae and in knee joints Elastic cartilage- makes up outer ear and the epiglottis (flap which closes over the larynx when you swallow) |
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Name, features and characteristic of muscle tissue? |
Muscle tissue is well vascularised (has many blood vessels) Muscle cells called fibres- elongated and contains organelles called myofilaments made of proteins (actin and myosin) These allow muscle tissue to contract |
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give 3 types of muscle tissue and their function. |
Skeletal muscle: packed by connective tissue sheets, joins bones to tendon and causes bones to move. Cardiac muscle: self-explanatory Smooth muscle: occurs in walls of intestine, blood vessels, uterus and urinary tract and propels substances along these |
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Definition of a cell |
smallest unit of life |
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What do single celled organisms do within a cell? |
carry out all essential life processes within the cell |
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When are multi-cellular organisms' stem cells formed? |
at fertilisation |
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What is the key term for stem cells changing? |
differentiating |
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go through the process of differentiation |
following fertilisation the zygote undergoes mitotic division where all genomes can be expressed. These are embryonic stem cells which are totipotent and can become any cell including placental cells. They can divide by mitsosis and provide more cells that can differentiate into specialised cells for growth and repair. |
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What is a zygote? |
A diploid cell resulting from the fusion of 2 gametes |
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What is mitotic division? |
Mitosis |
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What is a genome? |
A set of chromesomes in a gamete/ microorganism or in a cell |
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When do embryonic cells start to differentiate? |
as the embryo passes the 8/16 cell stage. |
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When embryonic stem cells start to differentiate what are they now described as having? |
they have fate. |
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How is the identity and roll of a cell determined when it starts to differentiate? |
by genes which are switched on.
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What does "switching a gene on" do |
determines the form and function of the cell as well as the organelles within it. |
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What is it called when stem cells differentiate? |
following a fate path. moving further from stem cell and closer to the destined cell type. |
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What are hematopoietic stem cells? give an example What is the opposite of a stem cell which can differentiate into anything? |
cells which are already partly differnetiated. Blood cells form from these. unipotent. |
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What is a neutrophil |
A neutrophillic (readily stained by neutral dyes) white blood cell. |
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Define an organ Define an organ system. |
groups of tissues working together to perform a same function a number of organs working together to perform a life function. |
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What are totipotent and pluripotent stem cells formed from? |
Embryo and umbillical cord |
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What are adult stem cells called and where are they found? |
Somatic cells and in adipose fate, blood brain and skin. |
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What do somatic stem cells do? |
act as a renewal source for repair and already partially differentiated cells. |
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Where are induced stem cells created? |
the lab |
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How are somatic stem cells used in cell therapy? |
they're used in drug and disease research. The collection and usage of them is tightly regulated and can be subject to some controversy. |
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How are stem cells used in bone marrow transplants? |
Restore patients blood systems after specific cancer treatments when the patients stem cells can be collected before treatment,stored and put back inside after treatment. |
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How can stem cells help drug research and developmental biology? |
New drugs can be tested on cells rather than humans or animals. We can study how cells develop and make particular cell types and learn how diseases are caused and what goes wrong. |
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How does regenerative medicine work? |
Stem cells could populate a bio scaffold of an organ and then be directed to develop and grow into specific organs for transplants. The patient'scells are collected and reprogrammed into ips cells and then used to make an organ! |
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What can stem cells treat? |
A number of diseases e.g type 1 diabetes by programming ips cells to become pancreatic cells. bone marrow stem cells can develop into liver cells to treat liver disease. Stem cells can also develop into nervous tissue which could treat Altzheimer's or parkinson's or repair spinal cord injuries |
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What is the digestive system used for? What does it contain? Give an example of the life processes it carries out. Give a condition of the digestive system |
breaks down food into nutrients and absorbs said nutrients into the blood. Esophagus;stomach;intestines plus associated glands e.g. liver and pancreas. nutrition to provide ATP and materials for growth and repair. gallstones- means you can't store bile (digestive enzymes) properly. |
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What is the Circulatory system used for?
What does it contain? Give an example of the life processes it carries out. Give a condition of the Circulatory system. |
supplies oxygen and nutrients to the cells and removes waste products. heart and blood vessels transport to and from cells coronary artery disease- can't circulate blood properly. |
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What is the respiratory system used for?
What does it contain? Give an example of the life processes it carries out. Give a condition of the respiratory system |
gives Oxygen to the blood and removes waste gases e.g. carbon dioxide. lungs,airways,diaphragm and Intercostal msucles Breathing and gaseous exchange excretion bronchitis- obstructure condition so reduces the efficiancy of gas exchange. |
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What does the excretory (urinary) system do? What does it contain? Give an example of the life processes it carries out? give a condition of the excretory system |
makes urine and expels it from body to remove the harmful stuff in it. kidneys,uterus.bladder Excretion and osmoregulation Kidney failure-stops ultra filtration of waste products e.g. urea from the blood. |
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what does the intergomentry system do? What does it contain? give a life process it carries out Give a condition that affects it |
Protects body from damage e.g. water loss or abrasions nails,skin,hair waterproofing protection, temp regulation eczema- causes irritation protection from areas underneath is reduced. |
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what does the muscloskeletal system do?
What does it contain? give a life process it carries out Give a condition that affects it |
Provides form, support, stability and movement Bones, cartilage, muscles, tendons, ligaments and joints support, protection and movement Artheritis- reduces obility of joints which in turn reduces their efficiancy |
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what does the immune system do?
What does it contain? give a life process it carries out Give a condition that affects it |
Organs and processes which provide resistance to infection and toxins. protection from pathogens thymus glands, skin, bone,marrow,stomach acid, blood immune response immunodeficiency disorders target immune system and suppresses it meaning the body is susceptible to invading pathogens. |
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what does the nervous system do?
What does it contain? give a life process it carries out Give a condition that affects it |
sends electrical impulses to communicate messages around the body. Brain, spinal cord and nerves allows communication, control and co-ordination polio- caused paralyisis |
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what does the endocrine system do?
What does it contain? give a life process it carries out Give a condition that affects it |
communication control and co-ordination glands that make and secrete hormones e.g. thyroid, ovaries and testes hormone unctions (some could argue hormones are a life process-emotional self) Type 1 diabetes caused by lack of insulin produced by pancreas |
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what does the reproductive system do?
What does it contain? give a life process it carries out Give a condition that affects it |
enables reproduction to occur testes,penis,ovaries, uterus and vagina reproduction (essential for the promise of future generations) ovarian cancer, STD's, damage to production of sperm etc |
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what does the lymph system do?
What does it contain? give a life process it carries out Give a condition that affects it |
Transports fluid back to the circulatory system and is also important in resisting infections. lymph nodes and vessels Immune response glandular fever- causes lymph nodes and glands to swell |
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What is the scientific term for a sperm and an egg? |
Ovum, Spermatozoon or haploids (They fuse together to produce a diploid nucleus) |
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When a cell is unspecialised what can all it's genes do? |
be expressed |
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What are erythrocytes and what can they do? |
carry oxygen from the lungs to respiring cells |
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What are neutrophils and what can they do? |
ingest invading pathogens |
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What are erythrocytes and neutrophils derived from? |
Stem cells in the bone marrow |
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Give the ways erythrocytes are adapted to carry out their functions? |
Small (7.5 micrometres) so have a large SA:V ratio meaning oxygen can diffuse across and reach all regions inside the cell. Their biconcave shape increases SA:V ratio so more hemoglobin can be packed in flexible cytoskeleton means erythrocytes can change shape and travel through narrow capillaries. most organelles lost at differentiation so more space for hemoglobin molecules in them. |
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How much of the white blood cells are made up by neutrophils? |
50% |
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name the features of neutrophils? |
twice the size of erythrocytes and each one contains a multi abed nucleus.
Attracted to infection sites by chemo taxis
function is to ingest bacteria and some fungi by phagocytosis |
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How is the spermatozoa built of it's function? |
many mitochondria-carries out Aerobic respiration ot produce ATP for unduliopodium to move and be propelle towards ovum. buily long and thin so can move easily enzymes reaches from acrosome once sperm has reached ovum enzymes digest outer protective shell allowing sperm head to enter. Head of sperm contains haploid mail gamete nucleus and very little cytoplasm. |
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What is special about epithelial cells? |
they have cilia |
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Name 3 types of plant tissue
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Epidermal, Vascular and Meristematic |
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What is Epidermal tissue on a plant?
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It consists of flattened cells that apart from guard cells lack chloroplast and form a protective coating. some cells are impregnated with waxy substances forming a cuticle to prevent water loss and to act as protection.
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What is Vascular tissue in a plant. describe it.
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Tissue concerned with transport
Xylem-vessels carry water and minerals up from roots to the rest of the plant. Phloem-sieve tubes transfer products of photosynthesis in solution (Sap) from leaves to parts of the plant which doesn't photosynthesis e.g. roots, flowers or growing shoots (can go in both directions |
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What does meristematic tissue contain?
Where is it found? What are the features of the cells in meristems? |
Stem cells
Roots,Shoots and in the cambium of vascular bundles Thin walls wit little cellulose, no chloroplast not a large vacuole and can divide by mitosis and differentiate into other types of cells. |
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How do mature cells arise from meristems
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As most cells mature they develop a large vacuole and rigid cellulose cell wall preventing further cell division. New cells arise from meristems by mitosis
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How do Meristems make Xylem vessels?
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Some cambium vessels differentiate into xylem vessels lignin is deposited into the cell walls to reinforce them and waterproof them it also kills them, xylem vessels form a continuous column as the ends of the cell break down leaving wide lumens to carry water and dissolved minerals
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How do Meristems make phloem vessels?
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Cambium vessels differentiate into phloem sieve tubes/companion cells Sieve tubes loose organelles and sieve plates develop between them. companion cells keep organelles and continue metabolic function to sustain sieve tube as well.
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What are the 4 organs of a plant and what do they do?
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Leaf:-Photosynthesis
Flower:-Sexual reproduction Root:-Anchorage in soil-Absorbs minerals and water-Storage e.g. a carrot absorbs a carbohydrate Stem:-Support-holds leaves up so exposed to more sun-transportation of water and minerals-transportation of photosynthesis products-Storage of Photosynthesis products e.g. potato tubers store starch |
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Name 10 specialised plant cells in a leaf
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Cuticle, upper epidermis, paisade mesophyll cell, xylem,phloem,spongy mesophyll cell, guard cell, lower epidermis
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Where are pallisade cells located and how are they adapted for their function?
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within the leaves
adapted for photosynthesis:-long and cylindrical- pack together closely and can still circulate air so CO2 can diffuse- large Vacuole- chloroplast positioned near periphery of cell reducing diffusion distance for CO2- lots of chloroplast- carrying out Photosynthesis- contains cytoskeleton and motor proteins-moves chloroplast near upper surface of leaf when sunlight intensity is low but further down when it's high so cells aren't damaged. |
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What are guard cells? what do they do? how are they adapted to their function? where are they located?
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Pair of Specialised cells within lower and upper epidermis
They don't contain Chlorplast and they control air and water loss.Light energy is used to produce ATP which actively transports Potassium ions from surrounding epidermal tissue into guard cells lowering their water potential. water moves in via osmosis and the guard cells cell wall swells and gets more turgid . Tips bulge and stoma open. As stoma open Air containing CO2 is allowed to enter the plant so photosynthesis can occur. waste oxygen can diffuse out of stoma. |
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Where are root hair cells located? How are they adapted for their function, how do they carry out their function?
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Root hair cells are on the outer layer of young plant root hairs. These increase the SA for absorption of water and Ions e.g. nitrates from the soil.
Mineral ions are actively transported into the root hair cells so water potential is lowered and water moves in via osmosis down a water potential gradient. Root hair cells have special carrier proteins in their plasma membrane in order to actively transport the mineral ions in cels to produce ATP needed for active transport |
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Why do plants need transport systems?
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Larger plants have a small SA:V ratio so need a supply of O2, CO2,Water and nutrients as well as minerals. plant aren't active and respiration is low so oxygen demands are low. the demand can therefore be met with diffusion.Demand of Water and sugar are high so plants absorb water and nutrients from the soil but gaseous exchange is needed to manufacture sugars by photosynthesis.plants need a specialised transport system for getting water and minerals to leaves and products of photosythesis everywhere else.
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What is the transport system in the plant?
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Phloem and Xylem
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What is mitosis used in? |
Growth and repair and Asexual reproduction e.g. green flies and plants |
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what are diploid cells? What are haploid cells? |
2 copies of each chromesome 1 copy of each chromesome |
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What happens if the cell cycle goes wrong? |
uncontrolled cell division leading to tumors e.g. cancer |
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how do Eukaryotic cells reproduce? |
duplicating it's contents and then splitting into 2 daughter cells. |
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What are the 2 big phases of mitosis and what are they? |
Mitotic- nuclear and cytoplasmic division (M phases) Interphase- elaborate preperation for cell division in a carefully controlled sequence with checkpoints. |
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What are the stages of interphase ? WHat is the purpose of the "checkpoint" |
G1/S or the restriction point G2/M checkpoint G0 checkpoint to stop uncontrolled division leading to tumors to detect and repair damage |
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WHat does having the sequence with interphase ensure? |
cycle can't be reversed the DNA can only duplicate once |
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WHat happens during M phase? (interphase) |
A checkpoint triggers condensation of chromatin ensures cell is ready to complete mitosis Cell growth stops Nuclear division (mitosis) occurs Cytokinesis (cytoplasmic division) 1 hour |
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WHat is the G0 phase? |
A resting point where the cell may undergo apopositis or programmed cell death , differentiation or senescence (ageing) Some cells don't experience it (epithilial) lining cells in the gut, Some (e.g. neuromnes) remain in this phase indefinitely or a long time. |
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What does the G1 phase do? |
control mechanisms ensuring cell is ready to begin S phase and DNA synthesis Cells grow and increase in size Transcription of genes to make RNA occur Organelles duplicate Biosynthesis (e.g. protein synthesis and enzymes needed for DNA replication) the P53 (tumor supressor) gene helps control this phase. (10 hours) |
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WHat does the S phase of interphase do? |
DNA replication in specific order housekeeping genes (all those that are active in all cells first then cells that are normally inactive in specific cells) commited to mitosis after entering this stage DNA replicates Chromesomes duplicated so eacho ne consits of identical, sister chromitids 9 hours) |
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Why is S phase rapid? |
to reduce chance of spontaneous mutations as DNA is exposed to mutagenic agents. |
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Define Interphase |
The phase wherew the celll is not dividing and is sub divided into growth and synthesis phases. |
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Define mitosis |
type of nuclear division that produces daughter cells genetically identical to eachother and the parent cell. |
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WHat is the number of cell cycles a cell shoud go under? WHat is this called? |
50 Hayflick constant |
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WHat is the G2 phase of interphase? |
special chemicals ensure cell is ready for mitosis and stimulate proteins that will be involved in making chromesomes condense and in the formation of the spindle cells then grow (4 hours) |
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Define proto-oncogne and state what happens if these genes mutate WHat is P53 gene? |
they help regualte cell division by coding for proteins that help regulate cell growth and differentiation-if they mutate they can cause apoptosis leading to a tumor P53 gene- tumor supressor- decreases division amd triggers 2 major checkpoints |
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What happens in prokaryotic cell division? |
reproduce using binary fission a form of asexual reproduction that produces identical offspring occurs in 2 stages DNA is copied Cells divide adding a new cell membrane to a point on membrane between the 2 DNA copies. |
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What are the 4 stages of Mitosis? |
Prophase, Metaphase,Anaphase, Telophase |
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How do Chromesomes copy? |
Each Chromesome has a waist called a CENTROMERE After replication the 2 copies are held together at this point in this state each individual chromesome is referred to as a Chromatid they become Chromasomes again once seperated Each dividing cell has 2 new sets of chromatids because it has 2 of each chromesome |
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WHat is the acronym for mitosis? |
PMAT |
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What happens during prophase? |
the chromasomes shorten and thicken as DNA supercoils. nuclear envelope breaks down centriole devides and the 2 new daughter cells move to opposite poles of the cell, Cytoskeleton protein threads spindle between centrioles. In plants the tublin threads are made from cytoplasm |
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What happens during Metaphase? |
the chromesomes line up in middle of cell and are attached to the spindle by there centromere |
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WHat happens during Anaphase? |
Centromeres divide seperating each pair of sister chromatids. SPindle contracts pulling chromatids to opposite ends if cell, centromere first. |
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What happens during Telophase |
Chromatids reach oppsite poles, uncoil and become long and thin again (they;re now chromesomes again) A nuclear envelope forms around each group forming 2 nuclei. |
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WHat is Cytokinesis? How does this occur in animals? How does it occur in plants? |
division of cytoplasm after mitosis the plasma membrane folds inwards and "nips in" the cytoplasm"Cleavage division" an end plate forms where the equator of the spindle was, a new plasma membrane and cellulose cell-wall material are laid down on either side along this end plate 2 new daughter cells are now formed, genetically identical to eachother and the new parent cell. |
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What is meiosis? |
A type of cell division that happens in the reproductive organs to produce gametes. |
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What does reduction division mean in terms of meiosis? |
Cells that divide have a full number of chromesomes to start with but after meiosis only have half the number (these cells are called haploid) |
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WHat happens during interphase (meiosis) |
DNA unravels and replicates to produce double-armed chromesomes called sister chromatids |
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What are homologous pairs of chromesomes? |
The Chromesomes are the same size, same genes, although they could be different versions of the same gene (Alleles) |
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What happens during Prophase 1 of meiosis? |
The chromesomescondesne becoming shorter and fatter and arrangeing themselves into homologous pairs and crossing-over occurs . centrioles start moving to the opppsite ends of the cell forming spindle fibres. the nucleur envolope breaks down. |
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What happens during metaphase 1 of meiosis? |
the homologous pairs line up across the centre of the cell and attach to the spindle fibres by their centromeres |
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WHat happens during Anaphase 1 of meiosis? |
The spindles contract, seperating the homologous pairs, one chromesome going to each end of the cell |
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What happens during telophase 1 of meiosis? |
A nuclear envelope forms around each group of chromesomes and cytokenesisoccurs so 2 haploid daughter cells are produced |
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WHat happens during meiosis 2? |
the 2 daughter cells go through prophase 2, metaphase 2, anaphase 2 and telophase 2 which is similar to mitosis in anaphase 2 the pairs of sister chrimatids are seperated and each new daughter cell gets 2 chromatid from each chromesome so 4 genetically different hapolid daughter cells are produced (gametes) |
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Describe what happens during "crossing over" of prophase 1 |
homologous pairs come together and pair up so the chromatids twist around each other and pair up and bits of chromatids swap over. the chromatids still contain the same genes but now have a different combonation of allelles |
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What are the 2 features of meosis that makes sure cells are gentically different? |
Crossing over of chromatids Independent assortment of Chromesomes |
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How does independent assortment lead to genetic variation? |
Each homologous pairin your cell is made up of 1 chromesome from your mum and 1 from your dad when this pair lines up in metaphase 1 and are seperated in anaphase 1 it's random which chromesome from each pair ends up in which daughter cell so the 4 haploid cells are completely genetically different this shuffling leads to genetic variation in potential offspring |
