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biology > Topic 3 ~ Voice Of The Genome > Flashcards

Topic 3 ~ Voice Of The Genome Flashcards

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AP® Biology flashcards
1
Q

What’s a capsule (prokaryotic cells)

A

Slimy layer on surface for protection and to prevent dehydration

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2
Q

What’s pili (prokaryotic cells)

A

Thin protein tubes that allow bacteria to adhere to surfaces

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3
Q

What’s cell wall (prokaryotic cells)

A

Wall that contains peptidoglycan to maintain shape

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4
Q

What are centrioles (eukaryotic cells) and structure

A

Hollow cylinders made up of rings of microtubules

Involved in formation of spindle during nuclear division and in transport within cytoplasm

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5
Q

What are mitochondria and structure

A

Site of aerobic respiration

Inner membrane folded into projections (cristae)

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6
Q

What’s a nucleolus

A

A dense body within the nucleus where ribosomes are made

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7
Q

What’s rough endoplasmic reticulum

A

System of interconnected membrane bound flattened sacs

Ribosomes attached to surface where proteins are made and transported through the ER to other parts of the cell

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8
Q

What is smooth endoplasmic reticulum

A

Like rough ER but with no ribosomes

Makes lipids and steroids like hormones

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9
Q

What is Golgi apparatus

A

Sacs of flattened sacs formed by fusion of vesicles

Modifies proteins and packages them in vesicles for transport

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10
Q

What are lysosomes

A

Spherical sacs containing digestive enzymes

Involved in breakdown of unwanted structures and in destruction of cells

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11
Q

Describe process of protein formation and transport

A
  • transcription to mRNA
  • mRNA leaves nucleus
  • protein made on ribosome
  • enters and moves through rough ER
  • vesicles pinched off ER contain protein
  • vesicles fuse into Golgi apparatus
  • proteins are modified
  • vesicles pinched off golgi contain modified protein
  • vesicle fuses with cell surface releasing protein like extracellular enzymes
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12
Q

What is the acrosome

A

Type of lysosome found in the head of sperm cells

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13
Q

What is the acrosome reaction

A

When acrosome in head of sperm break down the zona pellucida of the ovum

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14
Q

What is the cortical reaction

A

When sperm fuses with membrane surrounding the egg, chemicals are released by the ovum which cause zona pellucida to thicken preventing any more sperm to enter the egg

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15
Q

Describe the process of fertilisation

A
  • sperm reaches ovum
  • chemicals are released from surrounding cells triggering acrosome reaction
  • acrosome swells fusing with sperm cell
  • digestive enzymes released which digest through follicle cells and zona pellucida
  • sperm fuses with ovum membrane
  • sperm nucleus enters ovum
  • chemicals released by ovum thicken zona pellucida
  • nuclei of ovum and sperm fuse
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16
Q

What does diploid mean

A

Full number of chromosomes (46 in humans)

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17
Q

What does haploid mean

A

Half the number of chromosomes (23 in humans)

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18
Q

What is independent assortment

A

Random organisation of chromosomes as they line up during meiosis

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19
Q

What is crossing over

A

As chromosomes come together chromatids come into contact and break and rejoin, exchanging sections of DNA

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20
Q

What is Chiasma

A

Point where chromatids break during crossing over

21
Q

What is linkage of genes

A

Any 2 genes with a locus on the same chromosome are linked together and will tend to be passed on as a pair

22
Q

What is sex linkage

A

All genes on the sex chromosomes are passed on with those that determine sex

23
Q

What is a zygote

A

Fertilised ovum

24
Q

What is interphase

A

Cell synthesises new cell components (organelles, membranes, DNA)

By the end the cell contains enough for 2 new cells

25
Q

Describe prophase

A

Chromosomes condense becoming shorter and thicker
Chromatids are visible

Centrioles/ spindles move to position themselves at opposite ends of the cell

26
Q

Describe metaphase

A

Chromosomes move to the equator

centromeres attach to spindle fibres

27
Q

Describe anaphase

A

Centromeres split, spindle fibres pull the 2 halves of each centromere in opposite directions

28
Q

Describe telophase

A

Chromosomes unravel and nuclear envelop reforms so 2 sets of genetic info become enclosed in separate nuclei

29
Q

Describe Cytoplasmic division

A

Animal cells:
Cell membrane constricts around the centre. A ring of protein filaments bound to inside surface contract until cell is divided

Plant cells:
Cells synthesise new cell plate between the 2 new cells

30
Q

Meaning of totipotent

A

Cells that have the potential to develop into a total individual

31
Q

Meaning of pluripotent embryonic stem cells

A

Cells that can develop into many cell types but not all

32
Q

what is a blastocyst

A

a hollow ball of cells around 5 days after conception

33
Q

meaning of multipotent stem cells

A

also known as adult stem cells which are cells in adults that can develop into a variety of different cell types.

34
Q

explain how plants can be reproduced using plant tissue culture

A

small pieces of a plant (explants) are placed on a solid agar medium with nutrients and growth regulators. the cells divide to form a callus (mass of undifferentiated cells) which can be made to differentiate to form plant embryos that are genetically identical to the parent plant

35
Q

explain the totipotency of plant cells

A

unlike animal cells, many plant cell remain totipotent. many differentiated plant cells can de-differentiate and then develop into a complete new clone of the plant

36
Q

what is therapeutic cloning (somatic cell nuclear transfer)

A
  • the patient needing a transplant would have one of their diploid cells removed (eg from base of a hair)
  • the nucleus of this cell would then be fused with an ovum that had its nucleus removed
  • producing a diploid cell which can be stimulated to divide by mitosis
  • when the blastocyst forms, stem cells can be isolated and made to develop into tissues
37
Q

what is the epigenome

A
  • influences which genes can be transcribed in a particular cell
  • DNA is wrapped around histone proteins and both the DNA and histones have chemical markers attached to their surface.
  • the chemical markers make up the epigenome
38
Q

what is DNA methylation

A

methyl groups attaches to DNA which prevents transcription to mRNA as it stops the RNA polymerase from binding

39
Q

what is histone modification

A

the binding of epigenetic markers to histone tails alters how tightly DNA winds around histone proteins
- when wound tightly the genes are inactive so they cannot be transcribed to mRNA causing it to be ‘switched off’.

40
Q

describe the lac operon model for gene expression

A
  • studies the control of genes in a bacteria that only produces the enzyme beta-galactosidase to break down lactose
  • when lactose is not present a lactose repressor molecule binds to the DNA, stopping RNA polymerase from binding, preventing transcription, stopping the bete-galactosidase gene from being expressed.
  • when lactose is present it binds to the repressor preventing it from binding to the DNA so the gene is expressed, producing the enzyme
41
Q

describe how genes are switched on and off

A
  • RNA polymerase binds to a section of the DNA adjacent to the gene to be transcribed (promoter region)
  • regulator protein attaches to RNA polymerase
  • transcription occurs
  • gene is switched off if either of these arent attached
42
Q

how are cells organised into tissues

A
  • cells have specific recognition proteins/adhesion molecules on their cell surface membrane that binds to complementary proteins on an adjacent complentary cell
  • specialized cells can group themselves together to form a tissue
43
Q

what is phenotype

A

the characteristics of an organism (size, shape, blood group, sex)

44
Q

what causes differences in phenotype between people

A
  • differences in genetic make-up/genome

- the environment in which an individual develops

45
Q

what is polygenic inheritance

A

characteristics that show continuous variation and are controlled by genes at many loci, but are also controlled by the environment

46
Q

what is melanin

A

the dark pigment in skin and hair

47
Q

what are oncogenes

A

genes that code for the proteins that stimulate the transition from one stage in the cell cycle to the next.

48
Q

how could oncogenes play a role in triggering cancer

A

if DNA mutations occur or epigenetic changes, such as less methylation occurs, then it could cause the cell cycle to be continually active, causing excessive cell division.

49
Q

what are tumour suppressor genes

A

genes that produce suppressor proteins that stop the cell cycle.

biology (7 decks)

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